Welcome to the forum! The first thing you need to do is access Ed Felker's excellent crowd-sourced manual for Vegas/Axis. It's a sticky under "Motorhome Tech Topics."
Pay special attention to the part about the Use/Store switch. That's the first thing you need to learn. The search feature on the forum here will answer many of your questions. If you can't find it there, you'll find a lot of great help here.
Another good thing is to call Thor with your VIN and ask for all the schematics for your RV. They will be a good resource to answer some of your questions.
The oil fill is really high and some use a funnel and hose contraption to get oil into it. I've done that for oil changes and also used the battery access under the flip desk. The good news is you probably will not need to add oil between oil changes. The engine cover will not get you anywhere near the oil fill tube.
May the trails always twist in your favor
May the tales always end in good light
May you have more friends than one campfire can hold