Preflop is played perfectly. You don't want to get it in HU against the 3-bettor's strong range, but the hand plays very well in a mulitway pot, so you call and don't mind overcallers.

On the flop you have to do a little math and PPT work. Multiway pots are tricky, so we have to simplify. First, find out how much equity you need to stack off HU vs BB (leave the other players out of the equation for now).

The HU vs BB case

It would be reasonable to put BB on AA as a start. Find your EV against that. Then widen his range to include premium kings, and Broadway wraps (AKQJ, AKJT, and such). If he would 3B all of these, he would certainly jam any top pair+.

See how much of a difference there is between his AA-only and his TP+ from a wider, premium 3B range. If they are similar, it doesn't matter. If they aren't, the EV becomes sensitive to the range BB 3-bets, and it's important that you start with a reasonable estimate for that range.

The multiway case

After you have checked your EV vs BB alone, comes the time to think about the others. But if you can't call profitably vs BB, getting more players in probably won't help, since they will stack off with hands similar to yours, or better. You can explore that by doing a 3-way calculation where you add one player. Let's say someone who will stack off with any TP+ (since these are loose games).

Keep in mind that you will have to assign players reasonable preflop ranges before you do postflop work (all TP+ from a random **** range is not the same as all TP+ from a range that actually made it to the flop). For example, let's say you think UTG limps a 30% range (and doesn't have AA, since he didn't 4-bet). To find your equity when BB has AA-only and UTG has any TP+, you'd use:

BB = AA$nt ($nt = no trips, = no AAA*)
UTG = 30%6h!AA:(QQ,66,33,Q6,Q3,63,Q,AA-KK)

Now you can find your EV in those pots where UTG overcalls. Does it get worse or better for you, compared to the HU vs BB case?

Note that listing AA as a possible calling hand for UTG (the "AA-KK" par of the range to the right) contradicts the fact that we think he can't have them (the "30%6h!AA! part on the left). But it doesn't matter, we can still write it like this and PPT will sort out the combos automatically. 

Hope this gave you some ideas. The best thing you can do is to roll up your sleeves and do the work. There's no substitute for experience when it comes to understanding ranges and EV calculations.