Any lawn pro's with some advice?

I'm wanting to do some grooming on my lawn for a couple reasons. It's so rough / uneven from the years of mole hills, etc., with no real maintenance except for the usual mowing. It's pretty uneven with low spots and humps and bumps and the occasional tree roots near the surface that I have to go pretty slow with my riding mower.

I don't want the hassle or expense of tilling and reseeding the entire lawn, although I know this would be the best option...

What I was wondering is if it would be practical to bring in some sort of fill to be used as a leveler, then drag something around with my garden tractor to fill in the low spots. I would do this over the top of the existing lawn. Then seed over everything and hope for the best.

So can this work? What to use as the leveler, plain dirt? Reason I ask is I recall long ago that some people use a mixture with sand (?) I believe. What say you?

Thanks

Mark