Hi Derek, here are some steps that would probably be easier for building a piece like this, working more with solids throughout rather than by going around filling in little patches.

To start with I drew a curve:



Then mirrored it and extruded it out into a solid block:



Now use Fillet to round off all the sharp edges:



Then prepare another curve, I used Construct > Offset to offset the original curve inwards a bit:



Then use Boolean Difference to cut the solid by the offset curve, to make a sharp inside cut, leaving the fillet around the outside to be rounded:



Things can tend to go more simply and quickly by working on a carving out pieces away from a solid like this. Hope this helps,

- Michael