I also just sold my larger DVc contract--seller's remorse now! I'd keep the 3BR. I've stayed at GV and also a Royal Palms, next door to IP. Distance is equiv. Again, for someone who goes into the park in AM and stays all day, offsite make no difference IMHO. We used to stay offsite before buying DVC when our kids were young and they had a ball. We alternated park/pool-resort days. As they got older, as esp. when schedules didn't align, onsite for transport made a big difference for us. I like the GV pools better than M World Center--enough activity, but not too much.
For June, consider a character or sit down lunch--it gets you out of the heat or plan to go back to resort to swim early afternoon. Expect rain in the 4-6pm time, and then head back to the parks if you want. We grab breakfast in the room, hit the parks for 4 hours, come back and swim, eat dinner in condo and go back for late night. Your daughter is the perfect age for WDW. If she loves it, plan to come back again (and again)!
No way to know what will happen with FP or lines. Best bet is to go in AM by 9, bypass fantasy land and ride tomorrow or frontier until noon. alternate the next day. Try fantasy land later after little kids have left and forget about 7 dwarfs--it's not that great, I promise. Goofys Barnstormer, which is cute and fun is a walk on at 10 pm! If they have late hours this summer (doubtful) do them. Our most fun was at night--I had 2 sleeping 6 yr olds and a 10 year old on the bus at midnight--such a bad Mom, but such fun!