Found an even better method, yay!
Turn on Prescale Offset Editing in your World Settings dialog, run a selection around the area, feather it, then Global Raise the Prescale Offset a small amount. Then shrink the selection and do it again. Vary the amount you shrink the selection by and the amount you raise the Prescale Offset. It allows you to raise the elevation without losing the fractal map bumps. I'll post a map update tomorrow, I think.