Starcraft has not made the islander for quite a few years. The layout is great for open water trolling. The 3.0 will not be a power house but with the correct prop should be fine for 3-5 people but but speeds will probably be 30ish if propped for a heavy load. I had a sylvan skipper that was a very similar boat that I fished Lake Erie and Lake Ontario with for quite a few years.
With any used boat, condition is EVERYTHING! Any aluminum boat that has been run too hard could very possibly have loose or missing rivets, or cracked welds depending on brand. If not cover and or stored properly rotten transom and or soft floors are very possible. Even with low hours the boat could be in major need of repairs from neglect and or abuse.
One other thing to be careful of is the lower unit, I wouldn't consider an omc, mercruiser or Volvo penta only. Lower units need to have bellows and gears checked. A bad bellows can sink a boat and bad gears could possibly cost more to have replaced than the value of the boat.
If your not super familiar with boats I would suggest taking someone with you that is or paying for a marine survey. May sound over the top but I've been around boats my whole life and seen plenty of boats that were nightmares for the new owner that could have been avoided.