<p>In our case, we did the inviting, picked a place and treated the other family. As it turned out, next time they were in town, they invited and treated us, but I certainly wasn’t expecting that. </p>
<p>In your case, since the other family did the inviting, I’d say the odds are good that they intend to treat. Maybe their thought is that since you are local, you will provide more meals and/or an occasional home away from home for their child if the two become friends. In this case, it’s aside from the point whether or not the boys actually do become friends later or even whether or not there is going to be a next time - it’s a thoughtful gesture. </p>
<p>Since you are so inclined, you can certainly go ahead and offer to treat (especially would do so if you are the one who ends up choosing the restaurant), but I’d simply offer to split and/or accept gracefully if they insist . We generally prefer taking turns to splitting checks, personally. However, whatever you do, I would NOT make any comment on travel expenses. It implies you are counting their money and makes assumptions that are not only impolite, but potentially awkward whether true or untrue. In this case, since they are the ones who suggested dining out in the first place, I think it’s most likely a moot point, anyway.</p>