1. I've traveled the trails at the beginning of August and found that the trails are not crowded.
2. The LC is unaffected by the elevation. Recently had a rental hybrid Highlander which absolutely struggles at elevation by comparison. The LC is a dream to drive in the mountains.
3. Yes, you may need 4LO, particularly on the steeper grades. Some people have noted that the transmission temps go up - this is most likely occuring when you are using 4HI and creating a lot of heat in the transmission when you should be in 4LO. I spent a lot of time in 4LO on the trails, but switched to 4HI when I could drive faster on the flatter portions of the trail.
4. I had no issues getting gas. Ridgway, Ouray, Telluride, and SIlverton all have stations. Just make sure to fill up before leaving town.
We did Ophir Pass, Red Mountain, and Last Dollar Road plus some other places to get to hikes. Went up the Telluride side of Black Bear to the one way down section - personally no interest in doing Balck Bear even though the LC is more than capable.