It is never all that simple
[QUOTE=Lubylu;178043],,,, buying camping equipment then mixing and matching between camping and reasonable hotels. /QUOTE]
Are the boys used to camping? Do you know what sort of equipment you want/need? If the answer is żes'to both those questions, i would get onto sites like Craigslist now, for the city where you will be flying into. See what you can find, and if you can negotiate arranging to pick it up when you arrive.
Camping can be quite cheap, when camping on public lands - most of which have only basic facilities.
National Parks where the facilities are better, are a little more expensive, but are much sought after and limited in number. Mostly you have to book in many months ahead.
Then there are the commercial campgrounds which can often cost as much as a cheap motel, but have full facilities.
In or near the most popular national parks you need to book campgrounds as soon as you have your dates fixed.
Lifey