You need to find a local FB group or even Netmums :o - They will have suggestions of local attractions. I would also look on tripadvisor - sounds weird, but works.
But essentially I would make a list of the following within 30 mins walk/drive:
Parks
Swimming pools
Pet shops/garden centres with fish, birds, small animals
Soft play centres
Pub with beer garden/indoor play area
Libraries
Within an hour's drive:
Museums/galleries with kid friendly stuff
Woods/fields with animals/hills/other interesting outdoor area
Bigger/more interesting play areas, swimming pools
Children's/visitable farm parks
National Trust type places
Ruins, castles and so on
Ikea (kids love running around in there, and the cafe is cheap)
And then for rarer things, within 2 hours' drive:
Aquariums/zoos
Really special museums
Beaches (unless you're close to the coast and have loads, in which case put them in one of the other categories)
Amusement parks (may be better after age 2, or in a group so you can alternate childcare/rides)
Also family/friends you'd like to visit, invite over, or meet somewhere halfway and their relative distance.
Obviously these also vary in cost as well as distance but we essentially have a list of stuff we can do often, and stuff we do more rarely, that we developed for DS1 and we are refining for stuff they can both do.
Find out where local(ish) events are often advertised near you, too - local paper, facebook, etc.e