EDITED TO ADD: I was apparently typing at the same time as the OP was adding her update about her miscarriage. I didn't see the update until after I had posted this.
Sorry to hear about what happened. I did leave this information because I thought it might be helpful to your friend.
Hope you have a good trip and the trip helps you deal with your loss.
Sue
Emmaline Lola said:
My only thinking is, who will push you? or are you thinking about getting the electric wheelchairs? (I would have taken out a small village w/ an electric one

--so that was not an option for me)
Rent one if you need it, take care of yourself and your baby........and drink PLENTY of fluids...............
have a good trip
My thought also was who will push you.
You don't want to ask for electric (also called power) wheelchairs though.
The things they rent out in the parks and you can rent from off-site rental places are called
ECVs, or scooters. ECVs are steered like a bike and (after a short practice) are pretty easy to drive. One of the advantages of using them is that no one will need to push you. I noticed you have other children. Depending on the ages of your children, it might be hard for your DH to push you and deal with the children.
Power wheelchairs are more difficult to drive; you drive them with a joystick that controls both speed and direction. Because of that, power wheelchairs are only rented out to people who already have experience with them.
Someone already posted a number for one company; there are other companies listed in the disABILITIES FAQs thread near the top of the disABILITIES Board.
As was already pointed out, your friend is high risk because of being pregnant with more than one baby, so she needs to be extra careful. Dehydration and over-pushing are more of a problem than the walking. But, if either of you needs a wheelchair or
ECV, you shouldn't feel bad about using it. People
assume that you get all sorts of special treatment and don't have to wait in lines. That is not the truth though; most of the lines are wheelchair accessible and in most cases, you will be waiting in the same lines with everyone else. (So don't worry that you will be taking 'special treatment away from people with disabilities - we get very little special treatment).
As someone already pointed out, you want to vary what you are doing. Walk for a while, then ride for a while. Keep in mind that going back to your resort can be a bit of a long, tiring trip; so stop and head back there before you are really tired. If you do get tired and need to lie down in air conditioning for a while, each park has a First Aid station where you can do that.