My best advice is don't wait for the trip to wear masks. Start wearing them NOW. Wear them around your house. Get a few types and try them out. Wearing a mask is something that is going to take getting used to. You want to be able to wear it and not touch your face and adjust it. You want to wear it to the point where you don't think about it all the time. I'm not saying you won't notice it or it will become second nature, but the more you wear it, the better you will be able to ignore it and focus on other things.
I'm a nurse, and prior to the outbreak, I would wear a N95 for about 3 minutes once a year when I did my annual fit test (yes, there's a process to making sure a N95 fits because if it doesn't seal around your face, the fact that it can filter small particles doesn't mean a damn thing). I took care of a patient with TB a few times, but those cases have always been really rare.
Since being in a COVID hotspot, I can *mostly* comfortably wear an N95 for 10 hours without taking it off and without touching my face. Okay, it's not comfortable, but I'm used to it and it's bearable.
If you're not used to wearing masks, every mask is going to be constricting. I agree with PP that disposable masks feel lighter and less constricting, but that's not going to be enough if you and your family haven't acclimated to them.
So, my unsolicited advice is to have everyone put on masks and not take them off for half an hour. Maybe even do something during that time to distract yourselves so your minds have something to focus on other than the masks on your face. Then take them off, and do another short session a few hours later. Gradually increase the length of time you wear them. Is there a movie your family would like to see, one that would keep their interest? Spend a few bucks to rent it, and do movie night wearing masks to give them practice with a 2-hour wear time.
My other advice is to see if you can get masks with ties or over-the-head elastics. I personally find ear elastics to be irritating. If you only have make with ear elastics, get some sort of ear-savers. Sewing buttons to cloth headbands or baseball caps can be a great way to anchor the ear loops. I think it's a double whammy to have to get used to a mask on your face while something is digging into the backs of your ears.