You don't need a pressure regulator for your water system if you fill your fresh water tank and then use your on-board water pump. But if you plan to connect to 'city water' (with a hose), then you should have one. I never connect a hose to the trailer. I always fill the tank and pump from it.
You don't necessarily need to buy a bunch of Lynx Lego type blocks. If you have scrap lumber around the house, that works just fine under the tires and stabilizer jacks to help level the trailer. I have a variety of treated lumber boards I carry with me.
You need a water hose to fill your fresh water tank, or to connect to your camper. However, if you are accustom to drinking directly from the garden hose laying in your yard, then why spend a fortune, just because it's colored white? (I know, this is going to start a fire storm argument again... but to still the "waters" literally .... "To each his own!" My privilege if I want to drink from my garden hose that's had bugs crawling through it. I ain't died in 62 years yet.)
There are all kinds of sewer hoses. Eventually, they all go bad, even if they dry-rot. To begin your experience with a camper, I advise investing into the best one you can afford. Then add extensions to your collection that can add length over time. You never know how far you will need a hose to reach. Every campground, and every campsite is different.
I'm assuming you mean and RV level that will be attached to the side or front of your camper. Bad idea initially. You will struggle with your camper to figure out "what" is actually level and getting it level. Just use a carpenter's level from your tool box and level the camper with it FOR AWHILE. You will find the floor may be level, but the doors are swinging closed. or the counter top is level, but the refrigerator is out of whack. It will take time for you to figure out WHAT really needs to be level. After you figure that out, THEN add your level on the side of the camper so the most critical spot in your camper will have have a gauge to go by. Once you get your camper, you'll understand this. Don't spend the money right now.
Wheel chocks are probably THE most important thing you can have for your camper. Always, always, always chock the tires before unhitching ... even on flat ground. You don't need to buy "chocks" either. A concrete brick, a block of wood, a tree log, even a big rock can be used to chock the tires. But, definitely have something ready the day you take delivery of your new camper. But, you really don't have to spend money for one either when a big rock will do the same thing.
I'm sorry, I don't know what a "Jack Cap Block" is. So, I probably don't have one. But, it does help a lot to have a block or a set of blocks under the tongue jack. If the hitch on your tow vehicle is higher than the tongue jack will raise, putting blocks under the jack first will let you raise the trailer tongue higher. (vital when parking on slops and hills). Get a big hefty block at least 6-8 inches thick for under the tongue jack.
RV toilet paper is the biggest scam in the RV marketplace. You will pay way, way, way too much for something that is truly snake oil. Get whatever you use in hour house and ... that's that!
RV toilet cleaner is not necessary either. Actually, I've never heard of "RV toilet cleaner". If you want to clean the toilet, simply pour your dish washing soap down the toilet and brush the sides with that. If you are talking about cleaning the black tank, just flushing the tank with water, a lot and often will keep it cleaner than anything else you can do. A bit of laundry soap, or dishwashing liquid, and/or water softener for laundry down the toilet, go for a drive and let it slosh inside the black thank, and that's all you need to do. Why spend extra money, simply because it says "RV" on the label.
Same for your grey tanks. Drain them, add a few gallons of water, add Dawn dishwashing liquid, and go for a drive. Done! More is not needed.
Now, I've never used an electric drill to raise and lower my stabilizer jacks. But I'll give this one to you. But you'll probably still end up doing the final tightening by hand anyway.
Other folks have chimed in above with some pretty good suggestions. But here's the thing ... you do not need anything really "special" for your RV. Whatever you use around your house is what you use in your camper. This applies to dishes to your bath towels. Don't spend a fortune on "things" just to acquire a bunch of "things." Folks who have been RVing will all testify that after about 3 years of RV ownership, they start tossing needless junk OUT of their RV. I know, we've flipped just about every single item inside the camper about 5 times in 30 years... everything! And we have minimized what we actually carry in the camper now. Less is better. But having the "right" things and being smart about them is what it's all about.
Put together a small repair tool box with a set of pliers, screw drivers, including the square ended screw driver, some auto fuses for your converter panel, electrical and duct tape, rope, string, other odds and ends in the event you need to tighten a screw on the cabinet door hinge or have a hammer to break up a frozen bag of ice. By the way, a hatchet makes a great hammer. No need for a hammer if you have a hatchet, and the hatches is also used for splitting fire wood.
Good luck. Think smart, and remember, if its labeled "RV" you are paying too much! Some items, like sewer hoses ... you have no choice. Everything else ... you can find it much cheaper somewhere else.
