Blue text is general comments/clarification. Red text is where I see an issue.
Day one
Check in and Walk BLT to MK

Spend some time at MK
Boat
(MK > GF > Poly) or Monorail to Poly
(MK > CR > TTC > Poly) for tour by 1:30pm
Walk from Poly to VGF
Boat or Monorail from VGF to TTC to Epcot Monorail (You cannot boat from GF to TTC. The boat is a tiny loop (GF > Poly > MK). You have to take the resort monorail from GF to TTC (GF > MK > CR > TTC) and then transfer to the Epcot monorail line. You can honestly walk from VGF back to Poly, get some cool air and a break in GCH, and then head over to the other side of the resort by the DVC longhouses and walk to TTC and just go directly to the Epcot monorail line.
Spend some time at Epcot
Bus or Monorail to from MK to BLT
(There is no bus from Epcot to MK. You need to take the Epcot monorail line to TTC. You can jump on the Express line to MK (Express only goes TTC to MK and back) and then walk to BLT, take the Resort line and stop directly at CR (TTC > Poly > GF > MK > CR), or take the ferry boat from TTC to MK and then walk to BLT (you could also take the Resort monorail line one stop). If you want to avoid the Epcot monorail and leave via the International Gateway you can walk to an Epcot resort and then bus to MK and walk to BLT or take the Resort monorail line one stop.
Day 2
Checkout and Bus from BLT to HS

Spend some time at HS
Skyliner to RIV by 1:30 for tour
(You need to take the DHS Skyliner to the Caribbean Beach Skyliner "hub" and transfer to the Epcot line. Riviera is the first stop)
Bus from RIV to DS

Boat from DS to SSR
(You can also walk depending on where you want to go at SSR and where you will be at DS)
Bus from SSR to MK
(Fair warning SSR has an internal bus loop)
Boat from MK to CCV
(There is also a bus to WL from MK. You can also walk to CR and then take the "blue flag" boat from CR to WL. This boat runs starting around 3pm now that it has returned from the closures in 2020. You can confirm this time the day prior while staying at BLT if you really wanted to try it out)
Dinner at CCV by 9:00
Day 3
Boat from CCV to Ft Wilderness and CFW tour if available also to see Ft Wilderness grounds
(FW is huge and the boat launch is on the opposite side of the cabins. You will need to take the internal bus loop for the resort to get from the boat launch to the cabins. This is why people rent golf carts at FW.)
Boat to MK (
You can also take a bus from FW to MK. If you are going back to WL instead of spending time in MK you are probably better off taking the bus to cut out time. FW shares bus service with WL. FW is the first stop. I am not as familiar with the times this occurs since I do not frequent FW and WL much, but the mornings usually have dedicated bus service so past 9am-ish you are most likely sharing. Someone should confirm this though.)
Boat to CCV pickup luggage
Leave for flight at 3pm
WOW WDW transportation is really complicated. I read my comments over 3x, but please ask if something doesn't make sense. It's a lot to take in!