To me, it would make the most sense to move 4315-4329 to Charleston to keep that fleet at one garage to save maintenance money, just as 2210-2228 will eventually all be at Castleton.
Meredith can have older buses because it is a part-time operation. Castleton has the X10 full-time and the X14 part-time.
2400, BTW, went to Yukon.