How much conversion do you want to do? Columbia Games old Harn modules have a very medieval feel but a lower magic level (plus lots of good small town maps... ). But they may be hard to find these days (showing my age... ).
Putting my $0.02 into the mix in support of this Kickstart. I've done three Open Design patronages so far and they get better and better. Journeys to the West was tons of fun and I can't wait to see my (small) contributions in print (some crazy cultists, gutter rhymes and whatnot). Check it out!