OK, I've been pondering this myself. Here are my suggestions:
1. The Boardwalk "experience." Go to Jellyrolls, ESPN, and then start hitting all the bars at Boardwalk, Yacht Club, Beach Club, Dolphin, and Swan.
2. The Monorail Loop. Hit the bars at Grand Floridian, Polynesian, and Contemporary. Then when you're "happy," go into Magic Kingdom and watch Spectromagic and/or Wishes. I did this once on a business trip. I was there alone and had a night to myself. I started with a Crown & 7 in the (deathly quiet) Grand Floridian bar. Had a nice talk with the bartender. Then moved to Polynesian, where I talked for an hour with a couple who were "escaping" their kids for a drink or two. Moved to Contemporary, where I ate dinner at the bar. I was HAMMERED by the time I stumbled into the Magic Kingdom. I watched Spectromagic and Wishes, then took the boat back to the Grand Floridian. It was one of the best nights I've ever had at Disney! Relaxing!
3. The EPCOT drunk. Bet you can't handle a drink in every country! Don't look at it as a theme park experience, look at it as a night out. Talk to people in the bars.
4. Cab to Universal CityWalk? Not sure how much it would cost, but it's a similar enough to Pleasure Island.
I don't go to Disney to drink... but we usually enjoyed a night or two at Pleasure Island. Part of the appeal was that we could drink and not have to worry about getting a cab, or designated drivers. Disney NEEDS to come up with an alternative. Maybe expand Boardwalk? Let's start by relocating the Adventurer's Club there!