Ditto to what Will said.
There is a trick you can use to eliminate SOME of the tape problems. If you still have a 4-track tape machine, and a soundcard with 4 inputs, lift all 4 tracks at once. If not, you'll have to lift 1 and 2, flip the tape, lift 3 and 4, then reverse them. DO NOT, and I mean that, use "auto reverse" to play tracks 3 and 4, take the tape out and turn it over. Auto-reverse throws an extra gear into the power transmission from the motor and the machiine will run at a different speed going backwards, giving you a major arse-pain.
As for hiss, Mikey-boy's suggestion of Adobe Audition may well be the smart one. Audition used to be CoolEditPro, which had a KILLER noise reduction.....all you needed to do was "teach" it what the noise on that particular tape sounded like by playing a "silent" (ie, hiss only) portion of it. It then did a damned good job of cleaning it up for you. If that feature has persisted into Audition, whoopy-do. If not, you'd be best to think about stealing Waves X-hiss X-Noise and X-Click.
Oh.....if the 4 track used DbX noise reduction, forget playing the tapes in a standard cassette deck, they'll sound horrid, DbX is a law unto itself, much better than all domestic Dolby systems, and utterly incompatible with them (the two sides of their respective compansion curves don't match, and DbX has a few tricks beyond mere compansion, just like Dolby-S does)
EDIT.....lifting it at lower volume will give you more noise not less. Also, instead of cutting and pasting.....why not lift each "segemt" (if that's how you're doing it), into a sample player, and keytrigger them in, I've done this with quite a few vocals and so on lifted from 4 track. The problem with cutting and pasting is that errors are cumulative, if your segment is long or short by a few milliseconds, it doesn't take two many loops of it before it's half a beat out with cakewalk's time. I know nothing of Cakewalk, but assume it can run Dx Plugins, so those Waves one will load into it.