I don't know so much about renting gear but I do know that lori and oreganmouse are right about one thing. You have to go and get out there in the back country just to see and feel the things that you need to see and feel to really know what you might want to take on a trip for one night or a trip that you stay multiple nights, you just have to figure it out for your self. On an occasion, I trek with a few friends of mine and their idea of what they need is totally different than what I might carry with me and it all works out the same for every one.
Some of the things that they carry I don't even carry...at all... And then there are the things that you just would not l;eave home with out. One of my buddies still carries the old fashioned canister type stove and the thing must weigh 5lbs., but he carries it none the less and he seems like he really enjoys the thing too. I just couldn't deal with the thing but it seems to work just fine for him and he has had it a very long time too.
So with all this being said, you just have to get out there and give it your best shot. You would be amazed at the gear list that you can get worked out on an over nighter. Just get out there and start walking and I can promise you that it will take no time at all to get a great gear list figured out...sabre11004...