I don’t completely understand what you are trying to do,
but you can definitely do MPs outside a WA. They have to START in a WA, and END in a WA. It doesn’t have to be the same WA / the MP can go wherever during that time, including outside WAs.
I’m doing cedar-fence line mowing, which has similar challenges - Mapping approaches for split-rail cedar fence line mowing (Mower & Trimmer module)
The “reverses along MPs” brought up above might kill you. I would do a few tests. Plan for lots of testing and reworking.
Plan that for the rest of this season at least you will spend more time trying to get Yarbo to do what you want vs you just manually doing whatever you were doing before. Hopefully in 2027 it will be a time-saver.