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The Dolomites broadly comprise 4 ski regions which sit directly on the Sella Ronda, and some other satellite resorts which are more 'standalone' (although you can get to the SR from some, and others are interconnected).
If you like clocking up the big miles, I would definitely go for one of the SR ski areas. These are (Selva) Val Gardena, Alta Badia, Val di Fassa and Arabba. Each of these is a resort/area in its own right, and has its own piste map, but they sit at the 4 'corners' of the SR, so you can easily ski between them.
Alta Badia has Corvara and Colfosco which I've heard referred to as a Blue Paradise, and apparently have lots of nice hotels and foodie places. I haven't stayed there, but have skied some of the runs as an offshoot to the SR.
The main resort in Val Gardena is Selva, and this is one of the biggest towns on the SR. It's a great base with nice hotels (and we stayed in an Inghams catered chalet there, which was ski in ski out, and was lovely!). You're right on the SR itself if you stay in Selva, so access to other places is easy. There are other places within the Val Gardena area - Orteisi is a lovely little town/village just a couple of lifts away from Selva/the SR.
The skiing in and around Selva itself is great - easy access to Plan de Gralba, and the well-known 'La Longia' (a fabulous 10km run that is my favourite run ever), and a world cup run to boot. Lots of reds, and a couple of more challenging blacks.
Arabba is at the opposite corner of the SR to Selva. It is a much smaller town, but because of that it is very easy to get onto the slopes first thing - lift queues are much smaller (not that they're big in Selva). It's billed as having more challenging runs than the other areas, with a few long blacks, but they're well within the capabilities of an intermediate. I loved them!
We stayed at the Sport Hotel, which was perfectly located, and very nice. Not that small, but had a nice family-run feeling, and was very traditional.
Val di Fassa is the other SR 'base', but I haven't skied there really - it's next on my hit list.
The beauty of these 4 resorts is that you can just get onto the SR from any of them, and ski round it. No need for a piste map, as it's really well signposted - orange in one direction, green in the other. You just follow the signs of the right colour and you'll end up where you started.
I would recommend doing a complete loop of it early in your week, to get your bearings, and once you've done that, you can look at the piste map and decide which deviations you'd like to take (the SR itself just skirts round the resorts, so you can 'turn off' and explore a resort in more detail, and then get back on again - a bit like going round the M25)
It's worth going round both ways - it has a very different feel.
You have 2 options for your lift pass - either just the individual resort, or the whole region. YOu'll want the latter - it's about 10 euros more a day, but it gives you access to everything around the SR and beyond.
There are other 'tours' which are well worth doing:
a WW2 loop (includes some bus transfers as well as skiing)
A ski over to the Marmolada glacier - Arabba is the start point for this, from Selva on the other side, it's quite a stretch to get over there and back!
The 'Hidden Valley' is an iconic run - you get pulled along by horses at the end. Alta Badia is the closest start point for this, but it's easy from Arabba too (and doable from Selva, but you'd have to keep a close eye on the clock)
La Longia - easy from Selva, you'd probably have to clock watch from Arabba
Cinque Torre - don't know about this one - it's on the list!
One key thing to bear in mind - all the resorts are proper towns (not purpose built), so lots of accommodation is not that close to the lift. I pay close attention to that because IMO there's nothing worse than starting a day by trudging to a lift.
Another thing to have in mind is that there are apparently major roadworks taking place on the road from Innsbruck to some places in the area. Some of the tour operators are using Verona (or Venice) this year instead, but if you're organising the trip yourself it's worth finding out the implications. I know lots of people fly to Verona/Venice and hire a car anyway. We have only used TOs for the Dolomites, primarily for the convenience of transfers.
I don't know anything about the resorts which aren't on the SR (Kronplatz etc). But if you want big miles, I'd go for one of the 4 above.
In case you can't tell, I LOVE the Dolomites. It is ridiculously beautiful, the skiing is amazing, the on-mountain food is great, and you could go back again and again and discover something new.
Hopefully that helps!