Pretty much any simple 4-seat fixed gear 150-180HP airplane would do the job nicely, including the Cessna C-172/177, Piper PA28-150-181, Grumman AA-5/5A/5B, and Beech 19/23. The 180 HP planes would be faster, and cost only marginally more to operate, but would like cost at least $10K more than their 150-160HP cousins (that's the balance of market supply and demand at work). All are excellent choices for a first ownership experience due to their simplicity and good support. They'd all also be excellent platforms for your instrument training, as you're really going an IR to need to be making that run routinely.
No doubt plenty of folks will tell you need something with retractable gear or a much bigger engine, but that simply isn't so, and you'd be paying a lot more up front as well as in operating and ownership costs for capability you aren't planning to use. Given your current level of experience, a nice simple 4-seater makes the most sense for you and your mission. Fly that for a few years including getting your IR and some serious IFR experience in such a plane, and then you can decide if a bigger, faster, more complex, more expensive airplane makes sense for you.