Yes, the sheepsquatch quest will yield a Fixer. Do it at level 50 unless you get a Fixer plan in the meantime so you have a Fixer to carry the rest of the way.

To see modifications you can mouse over it in the pip-boy and hit X to inspect, you'll get this screen

[Linked Image]

To achieve anything in this game you must be prepared to dabble in the boundary of disaster — Stirling Moss