You dont have to stop crew skills in total, just stop sending them on crew skill missions... unless you send them on slicing missions.
Didnt read whole thread, but here is my experience...
At the point I am reaching Balmorra or Taris (pre-20) I usually have my slicing skill up enough to earn a couple of hundred credits every 7-10 minutes from crew skill missions (slicing).
It is almost not worth changing direction in game to gather a slicing node, cause they give 50-80 (IIRC). I usually send out both companions (starter and ship driod) and quest without them, unless I am Jedi Knight when I also got Kira. With slicing, by the time I hit 25 I am usually way past the 48k needed. (If well equipped with gear, you probably only need companions for elites and champions really. Unless you want the speed, without stopping for healing between every fight)
If I go for other crew skills than slicing, I also do as mentioned. Stop sending crew on gathering missions, until I have the money. But when you are at Taris or Balmora at level 23 (or even Nar Shadda), you bring enough credits in through quest rewards to have the amount of money for speeders and ability by the time you hit 25. Use your commendations to upgrade mods and equipment instead of money, and use decent drops too meanwhile.
And about abilities, I know for certain some of them is hardly ever used by me... i.e. I can live without them even if i use them rarely. No need to pay 1k+ upgrading them until I got my speeder, if I need to cut down on some expenses.
GL and HF