I would also recommend the longest, widest boat you can get.
I've had a 1672 for a long time, and 4 people is a bit tight, but doable.
Recently I picked up an older 18' Starcraft Mariner-V that has been modified to have a side console. WOW, what a difference 2 feet makes! 4 people can fish comfortably in this one!
If you are limited, that's understandable, but if not, go for size. Pontoon boats are great, by the way, but are big to trailer. Once in the water, they are awesome. (Says a recent convert a few years ago) I bought a stainless steel countertop grill and it really adds to the day.
Fishing, swimming, tubing, lounging around, sleeping and then grilling up some fresh corn, dogs and burgers makes for a GREAT day on the water! I have used my pontoon more in the last two years than my Princecraft in the last 5. With friends and family, too, not just fishing alone.