Probably best to find out if there are any tracks/clubs near you.
not only can you go there to see what its all about, you will be able to ask advice & actually see what the cars are capable of
also a local club will give you the option of competing with your car as just playing up the park on your own gets very old very quickly.....
don't be tempted for a cheap chinese car off ebay as you will break it & you will need spares. you can't get parts for the ebay specials.
go for a brand that is stocked by a local shop, they might also be a good source of advice/help when needed.
if you do have any local tracks/clubs make sure you buy a kit from a class that they support, once again no point having something you can't use locally!
if you go electric then yes lipo & brushless is the only sensible way to go, just make sure you buy a good balancing charger & your cells will last ages.
also read up on the Lipo cells charging & storage needs as they burn ferociously if mishandled!
the new Nitro engines are a LOT more reliable than the old ones & shouldn't give you much trouble.
somthing to consider is nitro engines are loud & will attract a lot of attention from the local chavs/constabulary. Chavs will ask how fast it goes before they try to steal it & the police will just tell you to stop.
the truck looking classes are very popular in the US but haven't really caught on over here & are not very well supported or even run at a lot of clubs! just do your homework & you should be fine
KillerV - Pace - Ringle - XTR M950 - Mavic - Azonic - etc....................