My feeling is that the K-28's would have taken over all operations out of Durango. The only use for the Mudhens would be possibly Montrose and lease to the Rio Grande Southern.
The operations out of Montrose could have easily been covered by a trio of K-28's, but getting them there and access to the shops at Salida & Alamosa would be a problem.
The RGS would be a problem. They would have to hope that the D&RGW would retain some Mudhens for lease, the D&RGW would be willing to sell the RGS a few Mudhens, or the RGS would be forced to upgrade it's line to accomidate the K-28's (highly unlikely). The latter would, of course, solve the Montrose problem.
The Silverton Northern locomotives could have been useful to the RGS, for they were newer and probably in better condition than the RGS's fleet of 2-8-0's. It's too bad that at least one of those locos wasn't preserved.
The C&S locos, if not donated for display somewhere, probably would have been scrapped. Same with the ET&WNC locomotives.
Regards,
Donald Foster