We bought our 20.63 Outback brand new in 2013. The handover from Caravanland in Perth was both rushed and not very concise. Best advice is to not allow them to rush it. Take your time and do a better job than I did. They glossed over a lot of things and i paid the price for it in excessive issues post purchase. If i was ever to purchase another Jayco ( not that i ever would) i'd have a need to go though everything. I would take out every drawer and try every self tapping screw for "tightenability". Nearly every one ( okay, maybe hyperbole, but would be at least 50%)had been overtorqued, probably with an electric screwdriver, allowing the screw to spin in a ,now, 'baggy' hole. As a consequence almost every wide drawer fell off a runner and were either lolling unevenly to one side, or rolling around the back of the 'van. The small ones under the wardrobe were fine. I had to redrill and refit with a gauge larger screw in order to make the runners stay where they were supposed to . Drawers were rattly and had not been adjusted properly by handover. I ended up doing it myself, but it should not be necessary.
Same goes for the drain from the washing machine that goes into the pipe that leads the grey water through the floor of the van. It is awkward to get to and the factory basly bent the saddle clamp and stripped both screws that hold it on. Similarly, the tap that feeds water to the washing m/c. Two different screws used and both could not be tightened.
Get into the dark places with a torch, make sure you point out that they haven't cable tied the excessive cables that you are sure to find for any slideout. On second thoughts, you may not be able to see too much as you need to take out the drawer and remove the panel brace strengthener for it. You will see a dangly length of 240v cable that feeds the power point under the table. I cable tied mine up as it was an accident waiting to happen. There is more if you want to take your phone and make a short movie with the light on the phone by stick your arm up the hole where the, now removed, drawer is and pointing it over the aforementioned strengthener. You will see uncontrolled electrical spaghetti. While you are at it, check the10 screws that hold that panel on. At least half will have untightenable self tapping screws.
On the slideout, when the water connection goes awry ( it will - trust me) ask how you are supposed to get at it to change it, as the back of the water manifold box is impossible to get at without dismantling part of the lounge seat. Once they know that you know, then get them to modify the seat with a flap or a pull out section to allow you to get your arm in to hold a spanner on the union that is connected to the where you fit the hose. This will be a marriage saver, if you have to do this yourself.This is assuming they have not seen the error of their ways in the interim and already made the suggested modification.
If you intend to use an electric caravan mover, which you may if you have a difficult driveway like we have, please check that you don't have cocky don't be rude welding on the jockey wheel mount. Ours peeled itself off the drawbar sending the towbar end crashing to the ground with a sickening thud. The penetration of weld was woeful and most definitely originally done by an apprentice. Shoddy and downright dangerous. Any doubts, just reject it, refuse to take it home and have them do it properly.
Get under the van and check the runs of cable and hosing. Ours was woeful. Electrical cables made off with a connector and a cursory wrap around with lecky tape that just fell off in short order. Check where the hoses and cables go through the floor and make sure they have sealed them. A lot of ours weren't and it caused ingress of road dust and a little bit of water. Not much to be honest, but for what these things cost, even a little is too much. If you have saggy cables get them to put on more cable ties or you will have to do it yourself.
Make sure the grommet where they pass the cables through on the draw bar is in place. On ours they had too many cables and not a big enough grommet and it was about to wear through cables until i noticed it was unable to sit in the chassis rail and was chafing.
Hatch lids under the bed have lifting handles, as does the one on the washing machine. These will break. See if you can con them into giving you a full set free. You will need them at some point and you will have to buy them. Unacceptable quality of manufacture issue.
Make sure the radio aeriel sits vertically, as you cannot get in the back to adjust it. Force it and you will break the really fragile crappy alloy they are made of. If they have left it just short of the horizontal, get them to adjust it to the vertical. I broke mine trying to adjust and had to devise something else to jerry rig. Looks don't be rude, but works fine.
Make sure that your wheelnuts are tight, as someone else suggested, but also make sure that they have not been overtightened either. Could not get mine off with the wheelbrace Jayco supplied and had to resort to a breaker bar and a piece of pipe to shift them. Fine in your driveway, not so good if you are stuck on the side of the road when it is pissing down with rain and you have a flat.
Check the caravan door lock. The barrel fell out of ours first trip.
Hopefully our unit was just a lemon that sneaked through QA unchecked. It totally coloured our experience in the wrong shade of cack brown. We will do one shortish 3 month trip from next month and will trade it now that we are talking of doing a big lap. I am guessing you are paying $80K-ish for yours. That is a substantial wedge of cash that you need to get value for money on.
Caveat Emptor. Any doubts, don't tow it home until you are satisfied. I found that getting Jayco to do anything, once money had been transferred, to be virtually impossible.