I think alot of it depends on your confidence level in WA. A few short years ago I would have said stick close and knowledge of area and elk would be more advantageous than trying to FIND other elk. But major changes have taken place in that time and I think its more of a case by case basis now. Im assuming you are looking at the westside, simply because your taking an out of stater who (presumably) will want a chance at a branched bull.
If hunting just for yourself, than scouting can pay huge dividends. We have some wonderful opportunities here for the guy willing to work hard as you have obviously seen. The seasons being pushed later helps, But if trying to kill multiple elk especially with an out of state hunter I would seek other states. From a pure logistics standpoint, fire closures, access permits will be a couple of big hurdles to over come. If you do have a piece of great public land that affords alot of opportunities over the course of the season then go for it!... I have not had great luck finding those, Most of the time when I find elk on public land/National forest the opportunties are scarce and tough to come by. Even during prime rut. But you know your friend better, so perhaps the challenge is no big deal and he is prepared for it.
I havent hunted Montana for elk, but have researched quite a bit and IMO both Idaho and Montana offer much better hunting on public ground. Montana is nice because it offers alot of area (most of the state) vs Idaho which is a "zone" tag. Both have plenty of public land. With Montana getting an edge in diversity of terrain overall. Montana also has a longer overall season if that matters. Wolves are in both states, but Montana it seems easier to get away from them. Although this could be simply impression on my part. I hunted Idaho the last two years, and last year no wolves, tons of bugling. This year wolves and less bugling. Other factors played in as well though. I think both states recognize the threat to their out of state revenue stream and are taking measures to mitigate it. Idaho is closer for me. Thats why I started there. Idaho tag offers some additional flexibility in animal species taken (look at regs for description) but thats a possible perk. From my research it seemed animal quality was better in montana, but there were more areas to get away in Idaho. Again conclusion drawn from research and not boots on ground stats.
A couple other thoughts..... I dont know if this is something your friend is considering making an annual event or if its a bucket list type trip. If so possibly consider going drop in or outfitted? get in deeper country, more likely in animals quickly and just more of the "total package"? I have never done it, but would love to someday. Another option if he is looking at an annual/regular trip is looking at Oregon. Its more diverse given the rosie\rockie options. Possibly a little tougher on the eastside than some other states, but good bulls are there and plenty of room to roam. Always had a fun time filling tags there. Good luck!
