I've found that it's easier to plan the vacation around the shops, rather than planning the vacation first and looking for a shop to fit into it. That can be frustrating if you have to schedule vacation time from work, however.
I can't tell you how many times I have been off work for a few weeks with no decent hotels offered, only to see a really great assignment then offered the same week I have to go back to work. If you know the frequency that the hotels are shopped (monthly, quarterly, yearly), you can sometimes plan on them showing up pretty far in advance and perhaps make a deal with the scheduler.
I have two more hotel assignments scheduled before I go back to work in April, and I'm probably just going to keep it at that. I don't feel as comfortable having a lot of money out of my 'kitty' these days. Even the hotels that offer reversal still have a lot of travel expenses and cash outlay when on assignment.