The last 2 BLT stays for us, the route was Poly, GF, CR and then VWL. Don't know if that is typical, though.
Since we only had small carry-ons (ME had our checked bags), we got off at the Poly and took the monorail to the CR. We easily beat the ME bus.
I usually plan on about 90 minutes from the time I step on the concourse to check-in counter. So, far, it hasn't been longer for that to get to either BLT or BWV.
As long as you land on time and barring any monorail issues, I think you will be able to make your 2 pm ADR at Kona.
FWIW, Kona isn't very busy that time of the day. If you have any worries about making the ADR (due to cc hold), cancel it and just walk in. Doubt you'll have any trouble, unless maybe if you are going between Christmas and New Year's.