Wow, your father had you at an old age. In my circumstances, I am the youngest child, there being many elder siblings who could be tasked with the care of our parent(s), which only leaves emotional needs to be met by spending time with parent(s).
I would wager that you already know most of this information, but if not, here goes...
When my brothers were about to deploy, many members of our family were there to spend their last week stateside together just to spend casual time with them, talk, laugh, watch movies, and send them off with hugs inside the hangar. I wasn't able to be there when they deployed (I had to relocate to another state in anticipation of my husband's redeployment in order to secure an apartment for us in preparation for his arrival) but while I was living in the same area as my brothers I did attend family briefings with them while I was able to. If your father can't be there for your departure, certainly make time to travel and to be with him at least for a few days, if not longer. This is not just for your sake of not having any regrets in case you might not have the luxury of being with your father again but also for your father's sake, in case anything happens which wouldn't allow your loved ones to see you or be with you again. Paperwork can provide for certain legal consequences of your possible death in the line of duty, but time with family is not something that can be afforded the way that material things can be if/once you're gone.
During any personal leave or free time you take, photos are something you should obtain of family or people you care about- with you in the photo or not, whether you think you'll need it later or not, obtain some. You will need to maintain morale and have some easily, self supplied mental and/or emotional support downrange no matter how tough or focused or hardened or unmovable you believe yourself to be, so think of something you can carry with you as a reminder.
If you won't be able to be there with your father before deployment through any possibility and you are an only child or the only child with a desire to support your parent in some way, it would be my concern that certain things are arranged for the parent, in the military for example in some scenarios you could become the sole person responsible for your elderly parent, legally, relocate him to where you are, get him an ID card that he can use to obtain certain benefits while you are activated, like health care, with you as his sponsor. If there is an MTF where you are that could also help.
There could be details of your situation which could prompt you to think of alternate ideas pertinent to your relationship with your father, his situation where he lives, his community where he lives, financial and legal implications, etc.
Consider that your father might have concerns or wants of his own regarding the fact that you could be leaving and possibly in a dangerous place within a year to possibly be gone longer than a year. Your father might have some thoughts to add on the subject.
Anticipate some way that you can keep in contact with your family and your friends or even friends, neighbors and/or church members who know your father and can get news to you concerning him if/when you are not able to contact your father. You could set up an e-mail address and be sure your father is knowledgeable in how to communicate with you, whether electronically or by snail mail, etc, and understands that there are certain details you can't share with him about your mission, location, unit, etc while traveling or during the deployment, etc. There are briefings which your family members are encouraged to attend if any of them are able to travel to where you are, but there are also family support groups for each unit and also rear detachment soldiers who can connect your loved ones to important resources.
Just wait and see. I've discovered in my life that romance for an INTJ just appears unexpectedly. You may meet someone and - that's it! Or nothing.
^
In the meantime, carefully consider what you want from this significant other, what the value of these wants is to you and why, and where you could meet that type of person. As my mother would say when she would ask my brothers what kind of woman they wanted to spend their life with and they then would describe a person with qualities very much like her own, "Well, the type of woman you've described by personality characteristics which you would prefer sounds similar to me, but I feel I should remind you that your father didn't meet me at a bar, so I'd bet you probably won't meet your ideal woman at a place like that, either, if she's anything like me." It's a lot easier to find the kind of person you want to find by ascertaining where that kind of person would be and frequent that kind of place in the time during which you're not leaving it to chance.
I wanted to spend my time with someone who shared a lot of my interests, and as it happened we met at a place where those mutual interests were easily accessible to be shared and discussed by dozens of people with the same amount of enthusiasm though their backgrounds were quite varied.
My last advice is to keep a journal if you don't already. Start somewhere, anywhere. It's better than verbal vomit. No one has to know but you. There are no rules to follow nor to break, all that you must do is write to have a very personal conversation with yourself on a thoughtful level. With a journal, essentially the goal is to just confess the truth to yourself- what your true feelings are about things and why. Some people are compelled to first lie to themselves before they can uncover what they are feeling beneath those cover emotions, what really fuels their actions, the why behind what worries them or what they fear, what's at the core of each idea or impulse- but that they are hesitant to confront.
P.S.
Don't rush to get married if you do meet someone who seems highly appealing. Certainly don't drop the line to anyone you may meet that you could be deploying within a year, as there are women who will be delighted to know they can try to take you for a ride to end up with at least half of what you own while you're in theater. If any of them try to say you're being ridiculous to want a pre-nup agreement in the scenario in which you do marry before deploying, remind them you'd be crazy to not legally protect yourself, it's not a matter of trust but a matter of common sense. Save the trust for the emotional stuff, not for your money. If you do meet a wonderful person before deploying, do try to get on the same page with this person emotionally so you both know what you're expecting and what expectations can be met or can't with full and complete honesty. If this hypothetical person really believes they can endure the deployment while staying within the loyalty of a long distance relationship with you, do everything in your power to keep the relationship healthy and to maintain communication, otherwise don't pressure anyone or pursue emotional connections that you will just have to sever.
Definitely don't give anybody you haven't known for quite a while any degree of legal Power of Attorney for any reason, as there are some people who will come up with sob stories just to appeal to any good nature they could sense in you and try to exploit that.