drums and bass

I do a lot of transfer work myself. (2 trk, 4 trk, 8trk cassette / 2, 4, 8, 16 trk Reel) It all depends on the source.
If these tracks were overloaded when you recorded them (recorded at +100db) then there is little chance at recovery.
Meaning no matter what you do... you can put a dress on a piece of crap but its still going to be a piece of crap.
Izotope RX can help with clean up for minor clicking, hum, buzzes, exc.
 
As an Example: in your case, I would suggested you re build the drums and bass parts.
If the original 4 track was done using a metronome it will be a piece of cake.
Simply line up the song to the time line and build the drum parts around it using soft synths.
Bass track is self explanatory.
 
I have done this on more than one occasion ( for a friend who lost his father and wanted to redo a track keeping his fathers vocals and guitar parts but adding his sons guitar and vocals.
 
With tape though be aware of the flux in the capstan motor. you might have to adjust the tempo in some spots to make up for the flux in motor fluctuations.
 

Not sure if they are on separate tracks, but if they are, you can try and convert them to midi and replace the analog recording with a nice new clean VST sound. 
The bass part is the easiest just drag the audio track to a midi track and Melodyn will convert it to midi. You'll have to do a little clean up work but I've done this to about 20 songs now and it works brilliantly. 
 
And the drums you might be able to salvage with Drum replacer. I did this last night for a kick and snare part, it was a multi track drum recording so I had 6 tracks. It was live and there was a lot of bleed which is why the drums sounded terrible but drum replacer saved the day and I now have a nice clean snare and kick track. The rest of the kit drum replacer choked on and I gave up. It doesn't seem to work with overhead mikes and hi hat. But with the snare and kick in the forefront I can mix in the other live tracks and it's nice and punchy now. Drum replacer has a mix slider where you can blend the original with the midi. 

Make copies of the tracks and eq and/or multiband to filter out/isolate…