Re: New 2 all this and need advice please
Welcome to the forum. BarelyAWake has given you some very good advise. I also would go with a simple cruiser type bike. The Walmart Schwinns or Huffys are a good choice. Regarding the trailer. I use an Instep lightning model and have for years for my dog. Very little drag and I don't think there's much any chance of exhaust fumes building up in the trailer. If you have the rain cover rolled up then also open up the rear one and air passes right through. But I don't think much exhaust could get in anyway with a stock muffler. If it was unpleasant my dog would not beg for rides. One nice thing about the trailer I use is that the connection to the bike is designed to flex so that if you were to wipe out the trailer will remain upright even if the bike is down (I know this from experience). I would also suggest that you pay close attention to your fenders, being sure they are firmly attached to the bike. And keep checking them. Since you plan on using a trailer and I am guessing your daughters will be riding (they are going to love it, by the way) I would also suggest rigging up a rear fender mudflap. You can buy one for pretty cheap from bikeworldusa.com or even make one from a piece of rubber car mat or an old piece of carpet. It keeps little grit and such from flying back and hitting the trailer. Even though the trailer has a mesh screen cover, the mud flap is still a good idea I think. I would also be sure to use the flag that comes with the trailer as it makes your whole rig more visible. I changed mine over to an American flag to get as much visual attention as I can from motorists. Especially with precious cargo, you really can not go overboard with being safe. Also a helmet of some kind for you Dad. Maybe cheap little bicycle helmets for the girls and strap them in with the safety belts in there. I always see bicycle helmets at goodwill and garage sales. The trailers are rated at a hundred pound cargo, but I've carried more and even gave a lady a ride in it once. Although not cheap, folding baskets which fit on each side of the rear wheel are very handy. When not in use they fold flat against the bike and when opened up each will hold a paper grocery bag. Made by Wald and also available from bikeworldusa or elsewhere on eBay. I hope this helps. Maintain your bike, give it a good install (ask lots of questions here) and you are going to have a viable, inexpensive mode of transport. Plus, a whole lot of fun!
Someday when I grow up I will probably lose interest in toys with wheels, but until then...