I've been slowly rehabbing the kitchen in my house and now it's time to figure out what to do with my floors. The situation is this:

- house was built in 1920, kitchen had maple hardwood flooring
- previous owner put an addition on the back of the kitchen in 1959, installing a plywood subfloor, then sheets of plywood, then lineoleum was glued on top of the top layer of plywood. The lineoleum was also glued over all the maple hardwood flooring in the original part of the kitchen.
- then carpet was laid on top of everything (classy, yes?)

I've torn out all the carpeting and pulled the linoleum off the hardwood floor. A flooring estimator said the wood's too far gone to bother refinishing (water damage, age, trying to match it with any new flooring, etc). I've also torn out the lineoleum and surface layer of plywood in the 1959 addition.

So as things stand right now, half of the kitchen has old (probably trashed) hardwood with glue residue stuck to it, and the other half has a plywood subfloor that's a few inches lower than the rest of the kitchen.

Obviously, I need to somehow level out these two floors, so I was thinking of taking out the old hardwood, seeing what level the other subfloor is, and then laying some new plywood subfloor over everything to bring it all to the same level.

Is it just as simple as doing some shimming and making sure everything is even all the way across?

Then, I was going to install prefinished hardwood flooring on top. Am I correct in thinking that it's basically as simple as laying down tarpaper and nailing the new flooring in?

One complicating factor is that I want to keep my kitchen cabinents in place, so I would have to leave the old hardwood floor there and cut around it. There's only two doorways - one has a transition already installed and the other has a metal threshold that extends onto the floor. That does limit me in terms of how high I can go with the floor.

Am I missing anything obvoius with this plan? Is floor-leveling best left to the experts? Any suggestions or guidance? Thanks in advance.