Personally I'd want something that can pull away from the traffic at 70. The OP has ridden before, so I doubt it will take too long to knock off the rust. I'd tend to say a 500 minimum. Depending on if there is the plan to ride off road much, I'd be looking at the DR650 or XR650L. If it was maybe some really easy trails then it goes to a 650 V-Strom or maybe one of the scramblers that are showing up. Just no seeing the 250 as an option. I rode a KLX650C for about 25 years as my all around bike. I now have a KLX250 and got a Yamaha XSR700 because even the 650 wasn't quite what I wanted for a street ride and it is losing a rod bearing. I do the 250 for dirt/gravel road riding, rode the 650 for everything, but it was really too heavy off road for me. The 250 is like riding a mountain bike, but just doesn't have the open road chops. So I did the 700. I could do a 500 and be happy, but no one made a 500 like I would want since 1983 when Honda made the VT500F Ascot twin.