Langadune, Packing a horse is alot different that riding a horse. If you are inexperinced at packing, go on the web and learn a couple of hicths and then find a pack saddle and horse and practice, practice,practice. If your pack slips, your going to have a rodeo. A rental horse for a hunt is around $400 w/ tack and you will need a trailer to get to the trailhead. Good Luck!
Where are you finding rental horses with tack for $400? that sounds like a good deal.
When I looked around for pack stock last summer the going rate was $600/season no tack with $1500 deposit. That is per head.
I think renting, borrowing, or buying stock for hunting has a lot of responsibility that comes with it, and one needs to know what their doing before they hit the mountains. It isn't riding around a pasture, and wrecks happen even with good stock and experienced wranglers.
I think someone DIY horseback hunting on rented stock is foolhardy at best. I don't mean to get on a soapbox, but IMO it is not a good idea.
Leave the horses, keep your expectations reasonable, come on out to Montana, and have a great hunt!