This past Nov. we did a split-stay between BCV 1 bedroom and BLT 1 bedroom with a 4 yr. old and 9 month old. BCV for HS and Epcot countries. AK moving day (we drove down), and BLT for MK and front of Epcot. We have also done this staying at the Poly Villas and Hotel. Didn't ride the bus one time (which we really dislike).
Get UBER to move you, not Disney. I highly recommend them. A transfer of us/bags from GF to BWI last month was only $7, probably 20 min. total and our room just happened to be ready when we got there.
I haven't seen any discounts on STANDARD rooms at the Poly this year, mostly other views/club (actually got a better deal at the GF last month??). I have seen a few Poly studios discounted though and you can rent points on them too, also at BCV and BWV.