Frankham is absolutely right about jazz styles not working in folk. I've made the transition you're trying to achieve, and the best advice I can offer is to play like yourself, especially at a reasonable volume.

Remember, less is more. Nice sustained whole, half, and quarter notes go a lot further than the overly "busy" sound of eighths, sixteenths, etc. This will make the bass blend in a lot more and keep you (already the object of derision and scorn for bringing an electric instrument into the room) from standing out too much. It also helps to sit on the amp or have the amp hidden under your chair. Finally, noting the emergency exits is also a good idea.

But seriously, a final suggestion: Buy an instrument with active pickups. The tonal range is much more pleasing, more adjustable, and less likely to sound like Grand Funk bass lines than a passive electronic instrument. I've been playing a 5-string Ken Smith for about 8 years now. Between the 5 strings, the unusual brand, and the wonderful woody tone allowed by the active pickups, tasteful playing blends in nicely.