Ok, I have seen "drop camps" on a lot of sites. This is my first year at elk and I would love to camp and hunt horseback. This may not work for me this year as I attempt to figure it all out. However the question here is where do I get information on these drop camps. I am reading my way through the Elk 101 on the CPW site and have not figured this part out yet.
Wow, where to start? Many of the fully-guided services offer drop-camp and/or semi-guided variations. I guess I'd recommend starting here:
http://www.coloradooutfitters.org/. Looks like you can do a filtered search for various options (including drop camps). I'm not sure if you're saying you'd like to do horseback with the drop-camp, but I don't think anyone is going to offer that. I know a handful of outfitters/guides locally, but I haven't actually hunted with any of them, so wouldn't want to give a personal recommendation.
Regardless of what type of service you choose, you're going to need to decide if you want to pick a service first, or an area/GMU first. I'd recommend the latter, though I realize that can be tough when you can't visit the area first (I'm assuming). CO elk hunting techniques vary widely, from open-prairie scoping and typical long shots to dark timber stalking. I grew up being trained in the latter, and since I can't sit still for more than an hour or so, that's what I do, but the success rate is probably a bit better for the open-country elk - if you can find them. So, kinda think about what type of hunting you want to do, then try to narrow it down to a general area; is it all about harvesting an animal, or is the experience (and scenery) also important? Are you more interested in high country/early season hunting (most wilderness areas would fit here), or later season BLM/private land/open country hunting (more "road hunting", sit-n-spot, etc.). To me, avoiding high-pressure areas is a higher priority than finding a trophy, so I look for the lesser-known GMUs, but ones that still have healthy populations. You didn't really indicate you were after a trophy bull, but if so, there's a handful of places in CO that most people would recommend to you - the northwest corner/Flattops, units 61, 40, 76, maybe 85. But if that's not your top goal, there are a ton of places you can get into good numbers of animals. There's a reason CO has so many OTC license units! That said, if it is a trophy you're after, you might do better to look at NM, AZ or UT - CO is more a "quantity" state vs "quality", at least measured in # of points on the rack.
One more resource, if you haven't already looked at it - the CO DOW has some helpful "regional hunt guides" here:
http://cpw.state.co.us/thingstodo/Pages/BigGameHuntGuides.aspx. These include statistics broken down by GMU, which are good general guides of success rate by season, etc. Definitely worth a look.