I did a trip in the Trinities last weekend.
We went in at the Swift Creek trail head, past Granite Lake over Seven Up Pass to Louella Lake on day 1. Day 2 was a day hike to Diamond Lake and a scramble to the top of Siligo Peak, then load up and hike to the top of Black basin. Day 3 was down Bear Basin back to the car.
We saw a few people walking around here and there, but had all the lakes we visited and all the campsites to ourselves.
Great trails with terrific views, I highly recommend the Trinities.
Last fall we did the hike you mentioned in your post. Car camping at Ripstein, then heading out past Canyon Lakes to "L" Lake. Great hike for a weekend, although I've read that it can be crowded during the high season.
From what I've seen, you can't go wrong in the Trinity Alps. I hope to make a trip there an annual event.
Oh yeah.......we just hung our food in trees in stuff sacks. The stuff above treeline is too steep to camp, you'll have at least a few trees around wherever you end up sleeping.