I'm in the early stages of plaiing this summers trip to WDW (very late in the game, I know ) We haven't been to Universal or IOA in a while, so we are planning to visit both parks during our trip.

We've talked about staying put at WDW and driving over, or possibly staying overnight at Universal Resort to take advantage of front of the line access.
I'm looking into Royal Pacific, because we've been to Tchoup Tchoup a few times, and liked the hotel.

Any opinions, is it worth upwards of $350 just to skip the lines?

I'd say yes, because it's part of your room key, however you could just buy the express pass seperately at ticket counter, but be warned, prices increase during the busier times so it'll probably be best to get a room and enjoy a night's stay there. You should be able to hit everything in both parks in a day if you plan carefully and use your express pass