I have a 75 year old house that is in decent shape. The PO did some
very clever landscaping where he raised the front yard right up to the
second clapboard on the house. I'm pretty sure it's the highest point
in the nieghborhood. The only reason I figured he did this was to rot
the musdills. He also did some clever roof flashing so that all water
that ran off the roof ran right onto the earth built up over the
musdills. That's why I'm sure he did all this deliberately to rot the
mudsills.

Anyway, I need to replace the rotted sections of sills. I am pretty
sure I understand how to replace them. Support the floor over the
sills to take the weight off them , knock out the old sill replace it
with new wood. I have read that you need to splice in new sections
rather than butt them up against each other and I wasn't sure how to do
this. Any info on this. Anything else I should consider?

Thanks for the help.

BTW, I am also fixing all the clever landscaping and drainage.