For example, after defeating their first opponent, the PCs would find a suitcase stuffed with 3,000 credit notes each denominated to Cr1,000. If the party accumulates more such treasures throughout the dungeon, by the end of the adventure, they'll have enough money to buy their first starship. Does this sound reasonable.
NO! It sounds totally silly!
Right, I'll preface the rest of my remarks by paraphrasing Hunter's sig - this is your game, play it the way you want.
Having said that, I think (IMHO) you're making the mistake of running Traveller the same way you would run D&D, just substituting guns for bow and arrows, aliens (or whatever) for orcs, and TL17+ 'nanite' drugs for healing potions.
(TL17+, by the way, is, AFAICR, beyond the capability of the Imperium, although I don't have my book handy to check).
Traveller adventures shouldn't be dungeon crawls - even if the characters are first level (and ignoring one of the adventures that came with the CT boxed set
Realistically, what sort of moron is going to leave cases containing MCr3 lying around so badly defended that a first-level party could gain one?
Even more realisitcally, do you not think he/she/it would
seriously beef up the defenses if the party managed to get even one case and then retreated? It'd be a good investment to spend even one case on a TL15+, 10th-level average mercenary squad - who would logically wipe out the party on its return
IMO, Traveller just isn't supposed to be run this way. Have a read of the Linkworlds Cluster pdf on this site and get your hands on other published Traveller adventures to see how it should be played.
Logic and 'realism'. And Traveller combat is (quite rightly) deadly, so any smart PC will avoid it except as a last resort or when the odds are greatly in his/her favour.
Assuming you do want to skip prior history and start with 1st level characters (your choice), then to get the PCs into space, you can use any number of other solutions. They don't need to own their own ship straight off - and shouldn't. Acquiring one can be their goal.
They're *hugely* inexperienced (in fact, incapable of running a ship safely!), so they'd be crew, deckhands or whatever, on a noble's yacht, merchant ship, or mercenary cruiser, getting into scrapes on shore leave and so on.
Skipping prior history, IMO, is a mistake. It's a big, dangerous, universe out there and PC's need at least some decent skills starting out. And not just the combat and shipboard ones!
I love and play D&D regularly. I love Traveller. But they are two very different genres and a typical D&D adventure, especially a dungeon crawl, just isn't a typical Traveller adventure, and probably vice versa. The best advice I could give would be to read as much sci-fi as you can get your hands on for adventure inspiration.
But at the end of the day, this is just my two cents worth. As Hunter says, it's your game, play it how you wish.
Regards,
Anton