Here is the Alaska page on elite benefits. You are entitled to SDC and refunds (service fee waivers) at the 40K level, though it has a note about no refunds/changes on X fare class (that may be the new basic economy fare - haven't run across those yet but they're supposed to be out there).
https://www.alaskaair.com/content/mileage-plan/membership-benefits?lid=nav:mileage-elite&int=AS_NAV_MP_EliteStatus_-prodID:MileagePlan
Alaska does not fly nonstop to Pittsburgh. You would have connecting options via ORD, or along the west coast. There's two BOS flights a day (morning and evening). They serve all of the DC area airports, though most of my trips there are on cheaper fares to BWI. There's morning flights to DCA and BWI which returns as the evening flights, and both morning and evening flights to IAD. There are other options with connections along the west coast with PDX and LAX probably being the closest connecting points.
There are two afternoon flights to AUS, though returns seem to vary from either one evening flight to both a morning and evening flight based on day. Again, you do have connecting options with LAX being the easiest.
BA can get you to Europe. Check the partner page for accrual rates. I credit my BA flights to AA to use my One World lifetime elite benefits.
https://www.alaskaair.com/content/mileage-plan/how-to-earn-miles/airline-partners?lid=nav:mileage-partners&int=AS_NAV_MP_AirlinePartners_-prodID:MPPartners
As to upgrades, most eastern routes from SFO are still flown on ex-Airbus aircraft with 8 seats. They are starting to be reassigned and you might start seeing some Boeing aircraft moved onto those routes (12-16 F seats) and ultimately all those Airbus planes will be reconfigured with more seats in F.
Keep in mind Alaska accrues 100% flight miles based on distance for coach fares, plus an elite bonus (125% at the 75K top tier). At top tier, you'd bring in over 11,000 miles on a $300 fare back east. There are additional bonus miles in play for higher priced coach fares and first class fares.