About to purchase our first RV

We are about to purchase our 1st rig, a 30' Winnebago Vista. We have a 140 lb Great Dane and are planning on spending 3-4 months on the road, Jan-April in the southern desert. My wife will need reliable internet connectivity and we will need to ensure our pup will be safe if left in the RV for several hours. I'm attempting to get an inspector to look the rig over before we buy. I'm looking for info about what upgrades we NEED and what upgrades we will probably want as well.