Future mother in law
You are going to spend way too much time with your mother in law in years to come. Take every opportunity to avoid unnecessary contact now, as it will only bring forward the day when you eventually get sick of her. It might even make you rethink marrying your girlfriend- have a look at her mum, that's what you've got in 25 years!
Take the same weight in fuel instead. It will give you options, peace of mind and won't be whinging the whole way. It won't throw up on you. Won't cramp style with girlfriend.
By the way I personally have a great preference for the 172 over the warrior:
- 2 big doors
-easier to get into
-roomier
-can stand under wing out of sun and rain while waiting
-better visibility downwards for sightseeing