what different routes can you take to get to this awesome-looking bowl (halfpipe). the last time I tried, i just hiked the bells trail to the reservoir and then offtrail from there but wasn't successful....ran out of time. haven't been up Bells for a couple years now. is it possible to hike the ridgeline on the left all the way up?

I've been there twice, both times in spring where there was a good amount of snow. Once via Bells Reservoir. Above the reservoir there's a gully that leads up to a notch behind Bell's Cleaver. This is all easy going. Then, a short steep descent into the bowl. Second time was out of Hogum, a long walk but pretty easy going all the way (on snow at least, it would be a rock hopping extravaganza in summer). If the big city spread out below isn't a turnoff, then Thunder Bowl is an excellent place to spend a night.

Depends on if you are using the bowl as an ascent route or just a ski descent and what time of year that it is.

If you just want a descent, and have a car shuttle, the route ascending from Alpine and to the top of South Thunder is probably the easiest.

If you don't want to do a car shuttle, it is probably easiest to go all the way up Bells to the reservoir and then through the notch between Bells Cleaver and South Thunder. It's easiest late spring and early summer, if you have an ice axe.

I think the ridge on the left while looking up at the bowl would be pretty difficult, though I haven't done it.

Also, one thing to keep in mind is that the bowl is awesome, but the bowl itself is not as steep as it appears from the valley floor in case you are interested in skiing it. Not sure if you are looking to skiing or just hiking.