I've received answers to most of the questions I had when we were talking with Sarah this past Monday. They might be of interest to others.
I had asked about the brand names of some of their options as I like to do some research on stuff for the trailer (and add in more bookmarks! HA!).
Water pressure regulator - Valterra (interestingly enough, ETI charges less than what I found it for on Amazon and that's not even taking into consideration the exchange rate)
Sand pads - Norco
Hitch lock - Master Lock
Wheel chalks - JR Products
Power tongue jack - Atwood 300lb Deluxe
Any of the Jack-E-Up devices will work with the power jack.
The size of the hatch for the underbed access area is 7.5" tall and 16.5" wide (although she did type in 19' so not 100% sure it's the same for the 21').
I had asked about installing the TP roll in a different area due to not getting the sink and was told we could wait until orientation to install it. (wanted to have more space by the non-existent sink for showering and the roll is right under the sink, so I thought it might be a good idea to install it elsewhere)
They can only install the one type of toilet they use (I had asked about a Dometic low-profile, elongated), so like someone else said, you get to toss a good toilet if you want to replace with another kind. Bummer. Hum, maybe a planter in my non-existent garden.
They don't use the Nev-R-Lubes, only the EZ Lubes.
The sink I want to install is 15x15x8 and it'll work. (Yes, I know I'll lose some space under the sink, but I'm fine with that, as well as any counter space. And no, I won't fill it up with water when washing dishes!) I was concerned it was too big, but Sarah said they can install it. The basin is appx 11.5x12. It has a single faucet hole in the upper right, but they can rotate it 90 degrees, so the faucet will be on the left, which I think will be better and more out of the way of doing stuff on the counter. I'm going to order it and the matching faucet from Pioneer Building as with the exchange rate it's lots less expensive than from an American vendor. I've written to them for a quote as I don't know if the one I got in Sept is still valid. So, two fewer things I need to haul up there when the time comes. Yay!
(I'm in love with this sink and faucet!!! So, I was excited to find out they would work. Never thought I'd be so excited about appliances. Never in my wildest dreams!)
And, as referenced in a separate thread I started, they will install the 12v heat tape. I just need to figure out which pipes and how much of the stuff to send to them.
I'm waiting to hear back on one more question and that's it. Yay!