Regarding conditions, keep in mind that this is a large mountain with lots of sun and wind exposure, as well as a lot of elevation variability in snowfall. In the Spring, on part of the mountain could be chalky powder, one part hellish crust, one part amazing corn, with conditions changing throughout the day as the sun hits different aspects.
On a powder day, the mountain will be a lot more uniform.
You will likely get more skiing in going WITHOUT a guide. Guided skiing tends to be on terrain furthest out from the lift, while there is a ton of terrain right off the lift or within a short 5 min hike. I've read a lot of accounts of good guided skiers getting about 4 runs in. Unguided it is not hard to double that.
Most skiing at Silverton in done in Slide paths- the trees tend to be tight and there is not always enough coverage in lower elevations. The Westside of the mountain is not threatening. The East side aka backside is a different animal. It is steeper, and generally bowls neck down to colouirs, ice falls, or cliffs. In many cases you can bail out of all of these, but if it is a dry spring the alternative routes many not have any snow on them. During unguided there are guides at the top of the lift to give advice- ask them specific questions about conditions before you commit.