I now live near Phoenix, AZ but lived in NJ until I was 50 and know about east coast rust - it is murder.
For whatever it's worth, I think you can put skins on east coast Jeeps if you take all precautions against rust.
I just put Poison Spyder brawler rockers and rear corners on my Jeep. Following Eddie's advice I ran a bead of silicone sealer all around the skins to keep water/mud/etc from getting behind the skins. And I painted the edges of the holes drilled for the nutserts (2 coats of Rustoleum primer and 2 coats of gloss primer) and then painted the nutserts themselves with the same 2 coats of primer and gloss topcoat making sure to seal the edges good (don't worry about paint getting all over the Jeep itself, the skins are never coming off anyway). And I put anti-seize on the nutsert threads and bolts to keep rust out of there as well. Painting everything well makes the install slower since you have to wait for the coats to dry but I think it is well worth it.
Since there is a small gap between the skins and the Jeep sheetmetal, there is air in that gap and that air has water vapor in it and that water will condense out when the dew point is hit so there will be some water in there from time to time which cannot be prevented. But by painting the nutsert holes and the nutserts, I feel that the Jeep sheetmetal will be pretty well protected and that any rust will be minimal at least for some number of years, probably more than 5 years.
If you intend to keep the Jeep for a long time there is definitely some risk of serious rust damage. But there is also risk of other types of damage so I say go for it! The skins look really cool.
Here are some pics showing the silicone seal, paint on the nutsert holes and anti-seize: