You will have a pack-n=play in your room already. I would, however, suggest bringing extra sheets for it -- namely the sort that do actually fit a Graco pack-n-play. It only comes with one set, and it's the ones that Graco provides with the pack-n-play, which I always thought were kinda scratchy (more poly than cotton). Bring a few nice mattress pads too (your typical waterproofing sort). I don't recall them providing these, and was glad I had brought some with me.
You may want to bring some sort of white noise machine with you, if baby is a light sleeper. It will make life easier so that you and your "built-in babysitters" can chat out in the main room while little nipper sleeps. Also will help drown out any possible occasional noises. At 5 1/2 mos, you won't need a highchair, but you should bring a good stroller that reclines. Those BWV hallways are somewhat long, and baby will be nice and comfy cruising along in comfort. We actually used a snap-on-frame for our youngest when we took her to WDW a few years ago (a frame with a nice basket that snapped onto her carseat). This way, she could stay in her carseat to ride the bus, then when we got off, just snap the frame back on and voila -- instant wheels. It was especially nice if she had fallen asleep -- no waking her to remove her from the seat, just unsnap the wheel part and go! We also took a backpack -- if your baby is sitting up at 5 1/2 mos (some do, some don't !) these can be wonderful. I found it ten times easier than any sling or front carrier, and all 3 of my kids loved the view up there (and dh didn't mind wearing it either -- it was somehow "cooler" than those other contraptions).
This may be more info than you needed, but what the hey, I was on a roll -- hope something in this is helpful!! My bil / sil are bringing their then-8-mos-old ds (and 4 yr old ds) with us on our next vacation to BWV. I can't wait to show our newest nephew the World!
