I know exactly what I'd do - if I still had my crafting knowledge. I'd head to Winterhold and set up a magic/alchemy shop next to the inn. Land has got to be dirt cheap in Winterhold and those burned down houses would be easy to raise and rebuild. I'd make connections with the Khajiit and the College and focus on supplying the mages with rare ingredients in exchange for enchanted goods.
Once my business made enough gold, I'd purchase 2 more of the burned down homes and rebuild them. I'd combine them into one large building and then rent it to the Khajiit caravans so Ri'saad could have a permanent base of operations in Skyrim and start an actual trading company. It would do them good to have a nice, warm place of rest too. Plus, Moon Sugar has a lot of magical properties and the Khajiit know how to get rare goods - no questions asked. They would also serve as my impromtu delivery service since the caravans make it out to all the hold capitols, and no one else seems to run any kind of goods delivery service in Skyrim.
Once trade has been re-established in Winterhold, we're going to need a port. The area beneath the college would serve perfectly as it's partially shielded from the winds off the Sea of Ghosts. The Argonians in Windhelm are unpaid and overworked and I'm certain I could tempt them over with decent pay.
In less than a decade, I could put Winterhold back on the map as an exotic trade center and port of call. With the influx of sailors, merchants and buyers, I'd then focus on the second stage of my plan: Entertainment in the form of gambling, magic shows and tourism.
The Shrine of Azura is already famous throughout Skyrim. Everyone knows about it, but few can make the pilgrimage because it's so dangerous. No more. I'd have armed carriages taking people to the Shrine and back - maybe with a cute spiced wine and sweetroll refreshment stand near the shrine. Sarthal is also in the neighborhood and I'm sure many patriotic Nords would love to visit the first city of men in Tamriel. It would be just like the Alamo.
Beyond that, in town I'd set up a casino with magic shows for tourists. Maybe mock mage battles with firebolts and wards, or trained atronachs in the same manor as lion tamers. The novice and apprentice mages at Winterhold need to train, and all those spellbooks cost money. I'm sure new mages would be up for a little more coin in their pockets for doing what they have to do anyway. And of course, we'd have to have our own Winterhold brand of alcohol. I'm thinking Vodka. Skyrim has enough mead.
And that would be that. Winterhold would be restored. Build a wall around the city, build a Dwemer Ferris Wheel and call it a day. I may not be the Dragonborn, but I'd be the richest man in Skyrim.