I find MegaTrav's system with Brownie points and the more detailed resolution of careers (a la Merchant Princes, High Gaurd, Scouts and Mercenary) adds even more. The BPs let you fudge a few 'or die' kind of rolls, get that extra special assignment to Sanitation School you always wanted, or whatever. They aren't really overpowering if you aren't 'medal cycling'.
And having college, military academy, naval academy, flight school, and merchant academy to enlist in is neat. The year by year determination of your activity also adds a lot to character history.
And of course, you can try for illegal anagathics to avoid the aging effects... at a risk... (and loss of cash).
This is part of what I *love* about Traveller - building a competent character at the BEGINNING of the game. One who has a history implied by his generation.
You might try the reprints of Books 4-7 and their more detailed systems. They're pretty good, though IMO not quite as good as MT.
OTOH, you should look for MTCG program
http://web.tampabay.rr.com/gsvenson/mtcg.html
It generates MT characters and also supports some extra things like Imperial Academy, some oddball careers, psionics, etc.
Have fun. The game really is quite a bit of fun and the metagame of building a character and explaining his background isn't by any means any less fun! (Or not much less anyway!)