It is a wonderful place for kids and dogs. Your dog needs a visit to the vet before you cross the border, making sure that he is in good heath and all his shots up to date. Don't bother to bring his dog food as they no longer let it across the border but it is easy to obtain here at any of the stores. They probably will want to see his paperwork as you cross into Mexico and might even take his picture (the dog, not your son).
You also might want to pick up a visa - making sure it is good for 6 months. They can be helpful if you are setting up a bank account, putting in for a long term visa (the old FM3 or FM2), or buying a house.
Shopping has gotten better in Penasco. There is a Sam's Club (US membership card is good here or you can buy one here); the Bodega, which is connected to WalMart, Super Ley and Santa Fe. One of the things we had to get used to was not a lot of frozen dinners to pop in the over. You do find your self eating much better - utilizing all the fresh fruits and veggies. Another thing my husband had to adjust to was the difference in taste of things that use sugar - now he doesn't care for US products that have a lot of sugar. Had a Fanta in the States last summer and it was so bad we tossed it - they, along with Coke, are soooo much better here.
You'll find lots of suggestions on where to shop for things and great places to eat from people on this forum. They truly are a great bunch.
Learn Spanish - at least a little bit. You don't have to as most here speak some English or will find someone that does. But if you are trying to learn it everyone is more then willing to help with your 'lessons' - your son will probably pick it up very quickly.
Driving around town: watch for Alto (stop) signs in the middle of the road or in hard to spot places. Stop. Don't expect other people to stop. Also be aware that people stop in the middle of the road to talk to friends - this is acceptable and you should either wait patiently or go around them carefully, maybe even saying hello yourself. Watch for dogs, kids, vendors, etc. in the roads - they wander. You will get spoiled driving here as it is much more relaxed then in the US - unless it is a holiday weekend lol.
There are tons of places to explore and enjoy, including the new movie complex. The Mall has started looking for businesses to lease spaces and, of course, the biggie is that the Home Cruise Port should start ground breaking soon - or at least 'manana'.
Ah, manana! Be aware that manana doesn't necessarily mean 'tomorrow', as in "I'll be there manana." Manana can mean different lengths of time. So relax - if it is a beautiful beach day the repairman you are waiting on has probably taken his family to the beach - so you might as well take yours
You will also find a lot of friends here - like most of the town. It is like the beauty of the sea brings out the beauty of friendship. Penasco is changing, it continues to grow, but the welcome stays the same - warm and friendly.
Now I'll quit taking up all of your time and let people who know what they are talking about get a word in.
Oh, for insurance you can't go wrong if you get yours through Rosie - she isn't only an agent but she is a friend and always there for you.
Welcome to Penasco!