For freemium players, I think you need to be at level 45 (in order to have the last free kid, Database) in order to have a good chance for the crafting prizes, and for phase 2 especially. It also helps to have some premium kids, but I only had the SVT which I bought half way through phase 2.
If you have the above, then you still need to sign in 4 times a day, once in the morning and then 3 more times every 4 hours (eg. @ 8am, 12pm, 4pm, 8pm ... and also do the 90 neighbor actions). This, along with some luck with bags, UFOs and good neighbors, should get you over the line in terms of the final prizes and most of the crafting prizes. The "glitch" of sending out Grems and then not logging in again until 4 hours later (and being rewarded with the full 4 currency per Grem, regardless of whether your neighbor tapped them or not) is also extremely useful, and combines well with the "log in every 4 hours" schedule.
This is what I did for this event and I've managed to get everything, having been a bit slack 2 or 3 days every week due to other commitments. If you can log in one more time per day (a total of 5 times, eg. 8am, 12pm, 4pm, 8pm and 12am), then all the prizes become extremely easy to get.
For premium players, having the Rigellian hunting license would have really helped, especially during the second phase (which was the most difficult).