I could never sell my horses x_x but leasing would also be -very- hard for me...
I've leased horses out, and leased horses from/to people.. and it is very fatiguing... Unless you -really- know the leaser... you have no clue what the leaser is going to do with your horse.
Example: I leased a mare that was rough around the edges from a private owner. Everytime i would get on her -everything- was a fight. Headset/collection, standing still, biting and bitting.. etc. After i was done training her, i got maybe a good 15 minutes of riding (after 45 of schooling) then the owner would get on and completely undo all the work i did. What wretches my guts the most, is I was PAYING HER 90.00 a month to TRAIN HER HORSE FOR HER. I look at that now, while im in my career of MAKING MONEY training horses and cringe.
Other Example: I leased Jasmine out for lessons (BAD IDEA). Jasmine is a beginner riding horse and is walk trot only. I really prefer she go in a snaffle bit because a beginner shouldn't be trusted with anything more than a snaffle, in my opinion. The people who leased her from me not only put a LOW PORT CURB in her mouth (she HATES curbs) they also CANTERED her... and due to her arthritis, she cannot canter smoothly anymore and it risks her falling over, and/or her severely injuring her legs. I told them it was walk trot ONLY with MY BRIDLE but they felt they knew better. Not to mention i watched kids rake the %$#@ out of her face and she kept looking at me like "Why? Why are you letting this happen?" I immediately said no more and took my horse back. She had a rough enough life.. i promised her retirement and my god, if i have anything to do with it, that mare will -enjoy- the rest of her life!
In your situation, you don't think you have a choice though? There is no way you could find a facility near you at college and board her? Even if it is a pasture board situation?
As far as the two options you gave.. I would pick Lease over Sale for the sheer fact of:
1: You don't want to regret getting an education and investing in your future because you had to sell your horse to do it. (if that makes sense)
2: You can always get your horse back from the lease.
3: You can still say proudly, that you are a horse owner.
4: As Jubilee posted, you can request pictures and status (put it in the leasing contract).
5: Make sure you know the rider who will be leasing your horse (to avoid a situation like i had).
Definately, DEFINATELY have a lease contract written up, LOL!
Best of luck girlie! I don't envy your situation one bit =/ You're handling it better than I would though, methinks.