Marlin 81 is a .22 LR, so skip the reloading thought.
It is a very good HUNTING grade rifle- it is not a heavy duty TARGET rifle. As you have figured out, the tube feed limits what you will do with bedding barrel, etc.
You best investment may be to do some ammo shopping, and see what your rifle likes best. Cleanup of trigger can help a little. Would mainly suggest that you love it for what it is.