^^ Your point is valid. I will see the horse every two months or so at competitions, and I've applied to college at Auburn. Best case scenario... I'm an hour away by the fall. Worst case, I'm around 3 hours away.
Again, it's a valid concern, but I think I like the combination
of my horse/this rider. I want the lessee to rack up some fame for my horse during this lease period -- miles, championships, points. This may be my best shot at having my cake (leasing out a horse) and eating it too (having that horse continue to do well competitively.)
It isn't totally ideal, and I haven't committed to anything in writing yet, so I could yank this lease at any time if the cons (out of state horse) start outweighing the pros (darn good rider competing the horse).
I'm leaning towards not charging anything extra monthly though. Just because that sounds like a pain to collect and deal with. Late payments, keeping dates, records...