"Although it would be a squeaker financially. $200 million is the low end of what I would estimate.

Been a while since I worked on fully-reusable SSTOs, so not sure what the best approach would be at this point."

How are you defining fully-reusable?
Can we agree that just the orbiter part of the Shuttle is not fully-reusable? But instead is repairable.

And if it could go "to a 27 degree orbit of 600 Km"
Wouldn't it be technically easier for long suborbital hop, which has less delta-v and less re-entry speed?

How much would estimate cost a fully-reusable SSTO, that goes suborbital and a distance of 500 miles?