If your taking the ME I would bargain on 1-1 1/2 hours (also depends on what resort and drop off order for them) to get to your resort and then check in could take 1/2 hour (less if you do online check in) , if your not taking your checked bags on the bus then maybe you just check in drop off carryon and go. Wait for bus (upwards of 10 minutes) then it’s average 15-20 mins to get to Disney Springs. So lunch is probably going to be early dinner. I wouldn’t go any earlier than 4-4:30pm. Also pending on where you book it’s a walk from the bus stops now as there is only the one central one.