First, my credentials vis-a-vis Bali: I’ve lived in Indonesia for a total of about 13 years since 1993, and I’ve spent a lot of time in Bali - I’ve been there more times than I can count, but probably 30+ trips. I also lived in Ubud for a month while volunteering for the Environmental Bamboo Foundation in Denpasar. Bali is an enchanting place (or a rolicking, rowdy one, if you prefer that kind of experience).
So - What do you want out of your trip, how long will you be there, how much money do you have to spend? All these things affect what is the right answer for you.
You can do everything in Bali from drunken revelry/nightclubbing with lots of hard-drinking Australians to quiet, pristine get-aways with sublime scuba diving. Beaches, batik, volcanoes, temples, exotic music and dancing … Bali has it all. You just have to decide what you want.
How good a shape are you and your mother in (and how old is she)? Keep in mind that depending on where you are from, Bali is likely to seem quite hot and humid. Cycling there could be beautiful - the scenery is fantastic - but also taxing if you aren’t ready to exert yourself in the heat.
Ubud used to be my go-to spot in Bali, but it’s gotten pretty touristy in recent years. Still, check out this site for information and ideas: www.murnis.com (Full disclosure - I know Murni and Jonathan, have stayed many times at the Villas and once at the Houses, and a couple of the articles on the website are reprints of articles I wrote for travel magazines.)
I actually think vegans may have a bit of trouble in Bali, unless you stick to the very tried-and-true, well-beaten tourist path, where they expect a lot of gaga “ooh! Eat Pray Love was such a life-changing movie!” types and have altered menus to match. Balinese flavor a lot of food with pork, duck, chicken or beef - there may not be a big hunk of meat in the dish, but there could well be some shreds of meat included. (Or take the rice cracker known as krupuk, for example - they are often flavored with shrimp or fish, so you may say to yourself, “oh, a rice cracker! It’s vegan” but it won’t be.) Eggs show up in a lot of food too. You will have to insist on eating tempe all the time if you really want to be vegan. Tempe is utterly delicious, so there are worse fates! Places like Murni’s Warung in Ubud will be able to serve you tasty vegan food.
Anyway, it’s a wonderful place and you’ll have a great time almost no matter what. I wouldn’t worry about language issues or personal safety. Be careful how much you pay for stuff, though, and bargain hard. People are happy to rip tourists off as much as they can.