I agree with others that have said first you have to decide what park(s) you want to visit more often. Remember, with hoppers you can't hop until 2pm. so if Epcot and HS are where are going to spend the most time, pick one of those resorts. If MK is where you are going to spend at least most mornings, pick one of those. I wouldn't discount WL either if MK is your thing, it's just a boat ride away. Keep in mind, the only way to get to Epcot from the monorail resorts is either the monorail or walk over to MK and hop on a bus there. Monorail is fine but not really my thing, it actually takes less time to take a bus and don't break down as often as the monorail.
Personally, we always stay at the Epcot resorts. I've stayed at all of them except the new Swan Reserve. Each has it's own little perks and advantages and you really can't go wrong. Like others, I prefer YC but tend to stay in whichever one is less, which lately has been Swan/Dolphin.
We have stayed at all three monorail resorts and for adults, GF is our choice. CR is just too contemporary for me, Poly is great if you have kids but it can be loud and a bit crowded with families.
As far as RIV and the skyliner. Keep in mind if there is a thunder storm or high winds, they will shut it down. You don't normally know it's shut down until you arrive there. If you are at Epcot and have exited the WS gate to get to it and it's shut down, your options are to go back through Epcot and catch a bus or walk (or boat) over to HS and catch a bus there.