3D job -redo 3D spline wrapped terrain mesh neatly, OBJ or FBX

Hello:

+ 3D job, need an OBJ or FBX 3D file modelled.
+ Should only take 2 or 3 hours, if that.
+ I have a 3D terrain, which was done with spline wraps. It is poorly made because bits jut into each other.
+ I need someone to remake this properly into 4 nice, simple, properly meshed pieces. See images.
+ The profile of the hills should be the same - note that the idea is that the hills have same cross section all the way around.
+ The bottom or base of the hills that touch the ground - the bit where they meet the flat ground plan - must exactly trace the existing one. If I drag and drop your work, I don't want to have to change the road layout or curb layout that this is part of.
+ No need to do the middle bit but it could be useful to trace for spline wrapping. Most of the hills follow it exactly <>
+ The triangular piece in white in the image probably needs to be done by hand with nice topology, it's a special case. Need that done in neatest way possible .It's okay if it juts into the hill a tiny bit like a seperate piece that slides in. Just need it done in a way I can work with.

As few polygons or loops or whatever as needed to get the job done.

Strongly recommend that someone uses something like Loft or Spline Wraps to do this - I'm simply too busy.

Hiring immediately, English speaking please.