If it's just a backup, my suggestion is to make a minimal investment to get it up and running so it's ready if/when you need it (and you may never need it). Leave the pickups. They might not be great, but they'll function in an emergency...which is what a backup bass is for. Honestly, the only thing I might change is the output jack. IME, those are the first things to fail on these cheaper instruments. This is a really inexpensive upgrade. If you're not comfortable with soldering, take it to someone that can re-do the wiring to make it work again. Heck, maybe you have a neighbor that would do it for free. IMHO, there's just no need to invest a bunch of money into a bass that is nothing more than an emergency backup.