When I go out there, I bring my full face helmet, elbow/forearm armor, and lower leg/knee armor along with a bunch of long sleeve jerseys. The added protection really helps with the confidence. One of the nice things about Mammoth is that if you do take a spill, the landing is generally soft provided you don't nail a tree or a rock
I wasn't a planning a trip out to Mammoth this year due to the birth of my 2nd daughter, but as luck turned out, I have a business trip out to Vegas in early September that will require me to stay over the weekend, so a friend of mine is coming into Vegas that Friday and we're going to head over to Mammoth to ride Saturday and Sunday. Trips to Mammoth can be done somewhat inexpensively especially if you can get a group of 3-5 people together to share costs. You can get a dirt cheap flight into Vegas and a relatively cheap car rental and then drive there (about 6 hours but very scenic). While in Mammoth, the summer lodging is dirt cheap - nice 2 bedroom condo's can go for as little as $500 for 6 days or you can stay at one of Mammoth's properties for as little as $70/night and it'll include a lift ticket. Food can be a little pricey, but that is to be expected in a little resort town in California.