I've managed to get the vast majority of the gold bricks, with only one minkit canister eluding me (the one with the nigh-impossible-on-a-PC green flyover trick in the "Rebel Attack" (Death Star) level of ANH. I've beaten them all in story and free play mode, imported the characters/minkits from L:SW 1, and I fiddled around with one of the "secret" levels outside the Cantina last night. I've gotten all 10 bounty hunter missions, and all that remains inside the Cantina is the Super Story mode on TESB and ROTJ, and the character and minikit bonuses, and I'm complete.
I think that the one extra that will do more good than anything else is the "score x" extra on several levels. I think it's pretty much impossible to beat some of the character bonus levels without one. I'm gradually going through the more "score heavy" levels to increase my total so I can at least get the double score extra.
Overall, the game is great, and a worthy successor (and dare I say improvement) on the superb L:SW 1 game. Loads of fun.