I think maybe just be patient like you have been, and keep trying to persuade her. I know it's hard to think of leaving your mother with people that you don't know. I have a wonderful caregiver for my mom for 8 hours a day, 3 days a week. I don't have any help on the weekends, but sometimes my son will stay with her on the weekends for a few hours and my husband and I can go to lunch or do something to get out. I live with my mom, so I don't even get to see my husband everyday. So just keep working on her, and I'm sure she will realize you are right. Hope you can find someone that you both can trust. As you know, it's very important to have time away from the person your taking care of. Even if they try and make you feel guilty, you need that time just to get away. Make plan for that county fair and go and have a great time. Enjoy! How about also maybe starting slow, like leaving her for an hour or so, to get away for maybe lunch or dinner, and then your wife will see how nice it really is, that you can increase your time. Hope it all works out for you

Great idea about starting off slow, a couple of hours to begin with. I would ask mrs pepper her concerns and worries for not getting in the help, If you can put her mind at rest or come up with solutions for her worries you might get things moving.
You write "pushing her to agree" I'm sure not in a bullying way and its not what you meant as such, but dont "push" as you will back her into a corner and make it all about what you need and want, and not about doing it because you love mrs pepper, and you want her to have a break and your doing it because you want to spend time with mrs pepper : ) make it about "her" and "us"
good luck

Mrs. Pepper is on board with the idea of outside help, she got it going again this time. Where she needs encouragement is with the idea of making it a weekend rather than a day long thing. We were able to do a week vacation about a year ago, but her brother was the one to stay with MIL.

I understand. I would have a hard time too, but hopefully you can find someone you can feel confident with and she will feel better. It's a hard thing to go through.

Does Mrs. Pepper still work full time? Taking care of or making decisions for or with an elderly parent can feel like a part time job. Not sure about Mrs. Pepper, but some women would find staying at home and resting and relaxing as attractive as weekend trip after a week at work, rather than adding on the 'work' of preparing to go out of town.

The cabin with all the stairs might be inviting if it is relatively close by, and planning and preparing for a trip there is relatively easy.

I do remember the BIL grocery shopping planning discussions from last year. Some arrangement like that, with a family member coming over could provide a good opportunity for you two.