I would probably make dinner ps for 7ish. That would give you time to get to your hotel, check in and freshen up if needed.
As for transportation - this will be the first trip I am using a town car. When I went with my parents we usually drove down. I've flown down 3 or 4 times and used Mears. Only once using mears did we not have drop other people off first. A half hour trip can turn into and hour or more when you have to wait for the van or bus to fill up and then make its rounds dropping people off before you get to your hotel. The same thing happens on the return to the airport - we ended up waiting at the airport 2 hrs for our flight (pre 9-11) b/c Mears had to pick up other people who had earlier flights. I'm willing to pay extra to not have to wait on other people. I've never had a rental car b/c we just wouldn't use it once we are there. All our activities are on site and we like WDW transportation. But that might not be best for you. I definitely would not recommend Mears unless you need to save some money. BTW I'm paying $100 round trip including tips for my towncar and it would seat up to 4 adults - Mears for 4 isn't much cheaper I believe.
Well there's my 2 cents - hope it helps.
