pros and cons for travel

My Mother has a bucket list and one that I want to make happen is a road trip. I have already decided to purchase a reclining wheelchair as she cant handle sitting up for long, that is going to set me back several hundred dollars. I have a cargo van and a ramp that I use for for my (work) equipment so I can get her in and out of the vehicle with no problem, but securing her inside is a big expense (tie downs cost hundreds of dollars) that I cannot afford by using the tie down systems. so I had a thought, I can easily secure a bed inside the van and get a nice high wedge for the bed so she can sit up and enjoy the ride without much expense. and I can add a seat belt to the bed. I thought of renting a wheelchair access van but that proved to be out of budget as well. can you think of any pros and cons that I need to know about my plan?