I would say you have a very good chance at a 275-300 bull in that neck of the woods. Most of the better bulls that I guided on were in the 290-320 range. Of course we saw a few bigger ones and I do think a few true monster (350 +) are in there. However the overall elk numbers are down. so you can go quite awhile between elk sightings. We have a group of guys from Texas that hunt the Sept hunt pretty regular on a drop hunt. They usually go 3 for 4 with one or two of those being bulls in the 300 range.
To be honest the numbers are better on the Salmon River side. Not especially numbers of bigger bulls, just number of elk. I have big hopes for this zone if they cut a few tags, kill a few wolves and the feed comes back after the fires. There has been more large fire activity in these units in the last 5 years, than in the previous 40 years...
I would say the cost of a drop camp is well worth it. Especially if you can get the outfitter to work with you on the price if you bring your own riding horse or something like that. You would likely have to promise them that you would not just turn around and come back on your own and put a camp on top of them the next year.... but most outfitters will work with you a bit on a drop camp, if you are a good guy and low maintenance. A wilderness hunt is more about the area and experience then putting several hundred inches of horn on the ground. good luck. Send me a PM if you want a Name or two of some outfitters.