Travel ideas for an international 70th bday trip

My moms turning 70 this year and my sister and I are planning an international trip to surprise her for her bday present. We are coming the western USA, my sister and I are both in our late 20s/early 30s and our mom who’s turning 70 is very happy spirited, loves nature and seeing new cultures. Sister speaks fairly fluent Spanish, my mom and I both speak broken Spanish and otherwise only speaks English.
We are not afraid of being out of our language (although it would make some things easier) but my main concerns are accessibility…my mom is able to walk but can’t do long distances and long or extreme treks are not in the cards. Also, she is a vegetarian (sis and I aren’t) so I want to make sure there are options for her. Looking for ideas on countries/cities that you’d recommend. We’re thinking a 3ish week trip, love nature, love local food/drink, don’t need high class staying arrangements as long as our 70 year old mom can sleep comfortably.
As of now we are considering Italy, Spain, Vietnam, Thailand, Japan, Australia, Tanzania.

Love to hear input!
Thanks