For me, the alien option is probably the easiest to complete because it fits nicely with my regular play style. Although I've had the game since day 1, I have not played with the retail stuff until now. I'm still not sure I like it. To me, that's the hardest option since they have to both max a career and run a successful business. Mansion Baron is just amassing as much money as possible. I say Alien is easier for me because I've never really been very interested in making my Sims rich, so focusing so much on money is a little boring to me. I've started with one of each option, but I may wind up scrapping this save and going with the 3 aliens like callycat did. We'll see.
A sure-fire way to meet aliens without the science career OR going to Sixam is to go to the nightclub in Willow Creek frequently. Most of the aliens are young adults and that's what gets generated the most at the nightclub. Strike up a conversation and if you have options like "discuss weird atmospheric pressure" or "discuss brain power" (these will have a little alien icon on them), then you know the other Sim is an alien. It's faster than waiting until you can go to Sixam. There are always aliens in disguise working in the science lab, too. You can join the career, meet some aliens, and then quit if that isn't the career you're pursuing with that Sim.
These suggestions may not work after the patch in a new save file. My game is generating very few townies and many are elders. Also, now the Science lab seems to be employing mostly premades (at least in my game). I know EA did some tweaking to fill NPC slots with preexisting Sims in order to address culling, but it's a little annoying to find Nina Caliente, Dennis Kim, and Vivian Lewis working in the lab. Guess I'd better get my rocket built sooner rather than later!
Usually, at the Blue Velvet, a few young adult Sims would be generated on each load. Now, the only Sims there when my Sim went were premades and only 2 Sims were actually visiting the lot. Frustrating.
