It's fairly easy with the chassis maintenance because the chassis owners manual has a list of the details required to keep the engine in top running condition, and to meet warranty obligations. But the actual RV maintenance is a little more difficult because there are important things to do on a regular basis that could cause loss of enjoyment if they aren't looked after.
One of the worst enemies of an RV is water. Water leaks will cause more deterioration, faster than anything else. And often, you won't know about a water leak until it's too late.
Some RV manufacturers actually stipulate in their warranty that the roof and sealer need to be inspected every six months. And in fact I would recommend doing it every three months, especially when the RV sits out in the hot sun most of the time.
The RV roof has a lot of possible openings where water could enter if the sealer starts to deteriorate. The roof vents, possibly the fridge vent, maybe a skylight or two are all places where seam sealer is used to prevent water leaks. But seam sealer doesn't last forever, and while some areas can just be touched up, eventually old sealer needs to be completely removed and new caulking applied.
Also, seam sealer deteriorates with exposure to sunlight, and so parking under a car port with do a lot of good towards reducing deterioration when the RV isn't being used. If you don't have a car port, a good quality RV Cover is another way of reducing that exposure.
Most North American made RV's have slide outs. Slide outs are the number one problem for RV service centers, so it's important to look after them. Regular slide out lubrication is something you can do yourself. Check with your manufacturer to see if you should use a grease, silicon, or dry lube.
Slide outs are adjustable, and they can go out of alignment, so it's important to check the fit of the slide out on a regular basis. If the slides start to bind it can cause damage, so alignment is important. If you notice a problem it's probably best to get an RV technician to properly adjust it.
One of the most common causes of slide out failure is simply low battery voltage. The motors that operate slide outs use a lot of current, and if your battery isn't strong enough, the motors won't operate. Check your RV house battery regularly to make sure it's still strong enough to operate the slides when you aren't plugged into electric.
Keep track of, and document your maintenance. It's easy to keep a file in your rig, and write down the dates that you check these things. Even if you don't plan to keep your RV for a long time, a future buyer will appreciate knowing what has been done on a regula basis.