My husband & I started out the same way, he has driven T/T for 15+ years and I had a Class A Permit with no experience. We also have two fairly good sized dogs one is a Boxer/Pitt Mix (75#) the other is a Bassett mix (50#). We found a good fleet owner who let me train in his truck and didn't have a problem with the dogs. As far as the dogs being in the truck they love it. They would rather be in the truck than us have regular jobs working 10+ hours a day and living in an apartment, they are always with us and get all the attention they want. As far as viciousness of the animals, we keep a muzzle close at hand for DOT purposes, truck repairs, etc. Most people have enough sense not to go up to a strange animal but, for those who don't, we never leave the doors unlocked or the windows down that don't have screens, which is something any responsible owner does(or at least should do). We have never had a problem with the pets not being allowed on certain properties either. I do know there are a few that won't allow them. Our company keeps us up to date as to which companies have that policy and we just refuse the load.(We haven't lost a load because of that yet and have been at it for 8+ months now). We argue, but I know other couples that aren't "trapped in a box" that argue alot more often than us, actually I think the dogs make it better because it gives us someone other than each other to talk to. Sorry to have rambled on... I'm not going to lie to you and tell you it's great. If it's something you want to do, you should do it. Hope I answered some of your questions.
Good Luck