Bird spring pass is fairly easy. It's about 2 1/2 hours and I did it when my jeep was stock. The bottom third towards the 15 is "gravelly" and you might scrape a little.
I just did Burro wash a couple weekends ago (good place to go swimming as well). It's a bit challenging in some spots but I met a guy down at the wash who did it in a stock 4xe. It's about 1 1/2 to 2 hours one way.
Gold strike pass is just around the corner from me. It's pretty easy and it takes about an hour.
The Nelson rollercoaster to the Nelson cut off road is a good one. There's other trails near there but I haven't done all of them.
I've yet to do Potosi Pass or Mormon wells road/sawmill road, but those are next on my list.
I don't know how much trail time you're looking for but the ones I've done are fun trails.