Software that corrects mixtape mistakes?

So I've got two 1200's and a mixer and I want to record a mix onto my hi-fi CD recorder. Realistically it's nigh on impossible for me to do a full 70 minute set without making some mistakes.

Now, I was believeing it would be a lot more feasible for me to record it in two parts, ie. to spend ages getting the first part on tape perfectly. Then to record the second set in another session. I would then like to splice the two recordings together using software, but I can believe of two problems with this.

1. The BPM is likely to be slightly different in both recordings.
2. The volume will certainly be different in both.

Because lets face it, I can make a note of the last record having the gain at 12 O'Clock or the pitchfader on the left deck being at roughly +4.5 but those kind of notes arent very accurate. So is there a (preferably cheap) piece of software that can do this basic task of mixing these two files together, without midi hardware, and also without using key correction/ timestretching technology as I want it to sound like a proper deck?

I would guess this is a common practice as I've rarely heard any mistakes on supposedly 'live' DJ compilation CD'd from the 90's & 00's, they can't all have been recorded in 99 takes. For example Ministry of Sound used Pro tools to correct Judge Jules mistakes on his mix CD's a decade ago, but the bulk of the mixing was done naturally