yes, if you really wanted too. the problem is the racer has really low ground clearance...you can get around this too with some modding like
this . this is just a 1:24 aoshima body and tsl super swamper tires on a racer with square inch up wheels (not mine). the suspension travel for the racer is nowhere near the same as the overland, so the rcaer will likley get stuck easily on uneven terrain.
i wouldn't worry about dust too much. the main concern is small pebbles and such mangling the pinion and spur gear.
if you want to go offroad...get the overland. you'll be much happier with it. you can always mod it for racing as well. if you want to race...get the racer and get some tires like in the picture above for very mild offroading.