Congrats on your new DP. We have had Gas, Propane and DHL motor homes and I feel the DP is by far the best choice. One the upside you get a much more substantial unit with more power, better braking, longer life, and much more.
On the down side they are much more.expensive to fix and maintain.
My first and best piece of advice for you is ... even if it is not a requirement in your region to get air brake certified .... do it anyways. In our area the 2 day course costs about 150 dollars but is well worth is. The majority of the course is on how air brakes work, how to identify problems and what to do if they occur.
Unlike hydraulic brakes ... Air brakes are an open system. This means that each time you thought the brakes you loose a small volume of air. If you are in the habit of pumping your brakes on the way down a hill, you can very quickly run out of air and find yourself with no brakes.
Air brake systems have and in line compressor that is constantly replenishing your supply .. However if is very easy to outset that supply.
On a general maintenance front I have been told by Cummins that you should never store a MH for an extended period with dirty oil ... As dirty oil is very acidic. I take my unit in for engine and genset service once a year just before putting it into storage.
Always let your unit come up to temp before driving it under load. This is easily determined through the Allison display.
Other than that ... not much different than gas