You can get up and over Hagerman Pass in an F150. I have done it in a Tahoe as well but that was no fun. Once you get over I would go all the way down, you will be on pavement for a bit, until you get to road 4B (N Fork Rd) towards Elk Wallow Campground. Burnt Mountain road has a gate that may be locked? I have only been up there for work and I have a key for it. The road is not great but did see a bunch of improvements in 2012 when the transmission line was being work on.
I am curious how the access is from Sylvan Lakes though as they did a bunch of road work last year I believe. Can you get in easier enough with an impreza?
I was up there this year from the Sylvan Lake side and a friend followed me in with a Prius, so unless things have deteriorated in the last month, you should be good to go from the north. Just FYI, the camping in the canyon proper was a real shit show. Tons of people, though admittedly, it didn't seem like the majority were climbers, so the crags were pleasant enough.