You don't really specify what your experience is, so I can't tell if you have previous "jet" time or not. Having said that there is no guarantee you will get the RJ as a new hire. However to answer your questions:
DEN/COS reserve can be as short as one month and have lasted up to around 4 months, based on how many new hires are being allowed there after you. Reserves AND lineholders are guarateed 10 day's off a month. However, most lineholders average between 12 to 14. SkyWest does not have any "Ready Reserve lines", but can use a regular reserve on ready if needed [no more than one per seat per airport at a time]. we do allow trip trades, but not between reserves and line holders unless it is on the reserves day's off and no comproimise of their reserve days are an issue. The ability to completely drop a trip is dependant on whether or not you can get someone else to pick up the trip also you may not drop below 65 hrs {I think thats the right number...it might be 62.5 hrs.}. There is no "Commuter Clause" and comutable lines will vary from domicile to domicile and can go senior. QOL as a commuter depends on your ability to bid the line. QOL as a commuter on reserve....SUCKS!
Hope I answered your questions. Good luck. SkyWest IS a good airline to work for in the regional industry. We have good airplanes, good maint., and a lot of domiciles all over the west {and ORD}. welcome aboard, when you get here.