I'll try to answer some of your questions, I'm sure others will have more specific (or more up to date) information for you!
1) Do all of these rooms really have boardwalk views? Yes. If I remember correctly, there are only a few of them (maybe 6 or 8) and they are right above the Boardwalk Bakery.
2) How has the food in the lounge been in terms of actual food and do they run out of things a lot? We were there last year at this time (almost one year to the day!) and the breakfasts were good (cereal, fruits, pastries), afternoon snacks weren't "all that" (goldfish, pretzels, m&m's, etc.), the evening hot appetizers were AMAZING (lots of different things usually from one of the restaurants on the boardwalk), and the desserts and cordials were PHENOMENAL!! I don't remember anything running out, the CM's kept things pretty well stocked, but I guess that also depends on the number of people there.
3) If I get put on a floor other than 4, exactly how far of a walk is it to the lounge? Are we talking the other side of the hotel or a couple steps down the hall and up some stairs? I've stayed Poly concierge so thats the only lounge I've ever been in so far. And just for curiousity, where is the lounge? Is it over any of the shops or restaurants just so I can get a visual of where it is?
Here's where things get a little...well, let's just say there is room for improvement. We were in room 3227 (middle window above Boardwalk Bakery) and it was a bit of a hike to get to the Lounge. There were two ways to get there, go back to the elevators and go up to the 4th floor, or go up the stairs (which were almost like a service area). We used the stairs because they were closer, but they were kinda weird. Well lit, and safe...just arranged in a strange location. It's certainly not the other side of the hotel, but it's not just up some stairs. The lounge is on the 4th floor, it is not really above any shops or restaurants...but you could say it's sort of above and behind the Bakery. It faces the general direction of Epcot (and a sort of "garden" area below). You can see some of Illuminations from the lounge.
One of our favorite parts of having a boardwalk view was being able to sit on our balcony and watch some of the "street performers" below. They were very entertaining!
The BWI is the only resort we've stayed in...and we LOVED it! I hope you love it too!