With what you already know about multi track recording, you should take a look at this
Tascam DP03SD Multitrack Recorder .
You can easily import BIAB instrument tracks (midi or RealTracks) into the unit and add your original parts to the backing tracks. It really is as easy as the old cassette Porta Studios. The 44.1/16 CD quality matches the BIAB exported tracks. It has editing features, Punch in/out, with Onboard DSP Effects and Processing. You can literally create a CD from start to finish without a computer for anything other than generating/rendering your BIAB tracks.
You are not limited to only 8 tracks because it can bounce tracks. It has a quality mastering features that is the same as used on the higher cost DP24/32 series hard disk multi tracks and there has recently been a substantial price drop making this fairly close to the price you're looking at.
I'm positive you can produce higher quality recordings straight out of the box with this unit (or the less expensive DP008 or DP006) than you will get using any DAW you are unfamiliar with it's operations. With the price drop, it's also worth the price difference.
Don't be fooled by it's appearance. It's not a toy.