Silly question but can I do these trails on my full suspension mountain bike, or will I be mercilessly mocked and possibly chased out of town?
I already have a mountain bike and a road bike so not keen to add a third!
There's always the debate / meme of "are gravel bikes just 1990's hardtail mountain bikes with drop bars?" and ... the jury's still out on that one ;-)
AFAIK a full suspension is an overkill, but if it's what You got, go for it. You'll just be a bit slower.
If You're looking for some testing, perhaps try to just get yourself a new pair of gravel tyres that fit Your wheels. That's by far the biggest source of resistance. If it's fun, pick up from there. There are plenty of videos on youtube on how to hack into a gravel bike a cheap old frame (either hardtail MTB, or some CX / touring frames). Doesn't have to more than 100-200EUR / USD in the end.
Yes. It will be a bit more work on the pedalling front vs a dedicated gravel bike, but I doubt you will encounter any bike snobbery. I have gravel trails near where I live, and you see all kinds of bikes tackling them.
I would however lock out the rear suspension, and probably the front too. The high volume tires at the right pressure will likely provide all the suspension you need for gravel and your pedaling will be more efficient.
As far as being mercilessly mocked, that reminds me of an old adage. We spend our youth worrying about what other people think. In middle age we decide we don't care what other people think. As we get older, we finally realize no one was thinking about us.
> I already have a mountain bike and a road bike so not keen to add a third!
Why would you say that? :)