The cheapest and IMHO the best solution is to buy a standalone CD-recorder with a CD-RW Audio (unrestricted) and do one side, then rip the CD, erase it, do another side and so on...
Cleaning and adjusting the cassette deck is a must, otherwise GIGO (garbage in...).
Instead of the cheap nowadays CD-Recorder one can use Tascam, Sony, Zoom or Olympus portables which have a super-quality but use SD or CF cards instead of CD-R/W with more space (no need to erase). They also record at other than 44k1 sampling rates.
Yet another solution is to use a standalone DAT deck in pass-through mode (ADC) and receive the SPDIF stream into the computer. A DAT recorder is better than a CD recorder (except for pro units), and it also can use the 48k sampling rate.
A good site with such info, in particular the setup of a cassette deck for digitisation, is tapeheads.net. It is accessible also without a registration (like doom9).
I repeat, if the deck is not up to the game, then the deck.headphone.output->laptop.mic.input would NOT be the limiting factor.
