If you really do want to check out the resort for possible future visits, then there's absolutely nothing wrong with this.
When we were there in 2001, we were staying at the Caribbean Beach resort. We had dinner on our third night at 1900 Park Fare at the Grand Floridian. After dinner, my husband said that he really liked the atmosphere of the resort and wanted to see what the rooms looked like, for a future stay. We went to the Front Desk and a very lovely CM there showed us around the grounds, and showed us a room. On the walk back to the main building my husband asked her if they had any castle view rooms available, immediately. She checked on the computer and made a couple of phone calls and told us that they did have a lagoon and castle view room available. Well my husband shocked me when he said to her "Ok, I'd like to check in, and we'll be back as soon as we check out of Caribbean Beach".
The CM was wonderful; she took care of everything, including having the remaining of our balance which we had paid in full before the trip, transferred over to the Grand Floridian, so we only had to pay the difference in price between the 2 resorts.
Back at CBR, the CMs there were wonderful too, and actually drove us and our luggage directly over to the Grand Floridian, instead of us having to take a bus and then wait for our luggage to arrive later.
A few days later when we were staying at the Grand Floridian, we were having dinner at the Kona Cafe, and we did the same thing. We asked a Front Desk CM to show us around the resort and to show us a room. We decided right then that our next family trip would be at the Polynesian, and that's where we're staying in 2 months
So, that was a long answer to your question, but to sum it up: Yes, you can ask for a tour of the resort and to see a room
(As long as they aren't busy with people checking in).
