I will be new to RC trucks soon. I want to use one in my yard which is mostly grass. What will work best, gas or electric? Also what do you recommend?

If you can afford a gasser than go with that. It will be able to conquer any terrain you may have because they are so large. electrics are cheaper though, and much smaller as a result.

Either works well, its what you would prefer. Do you like messing around with engines or would you just like a car that you charge up and runs?

I think he meant nitro, not gasoline.

drjgarage being new I would recommend an electric, they're much easier to start with and not so frustrating. When you're new a nitro can get overwhelming.

Any suggestions as to what truck would be good? This may be a question with lots of different choices but there may be a majority of one. Is there a kit out there that starts as a 2wd and then you can make it a 4wd?? Doesn't grass eat up batteries and motors more than fuel kits? What's the difference between gas and nitro?

Grass is harder on motors and engines so while you may get lower run times with electrics in grass the same is true for nitros.

90% of combustion engines in RCs are nitros not gas. True gassers are 1/5 size, more than 3' long and use gas from the gas pump. Nitros use a mix of fuel which includes a percentage of nitro, 15 to 30% usually. Unless your back yard is measured in acres a gasser is not a good choice for a back yard basher.

If you're in a rural area with the space then a gasser is a lot less maintenance than a nitro but you need a lot of room, they also start at $1000 so they are top of the chain in price too.

If it's mostly grass I'd suggest 4WD monster trucks.

*forgot to mention that if you live in an urban area then electrics are better choices. you're neighbors won't like the high pitched sound from a nitro, think gas lawn mower but higher pitched.