Kuching is very cheap to live in, but property prices have been increasing quite a bit. Kolo mee is the benchmark but laksa can be double in price.

Also, remember that Borneo is an island so everything that is not local is more expensive than KL, as you'll need to cover the shopping costs etc. Same for flights to anywhere, you normally need to add KCH-KL leg and the time.

A non Sarawakian would need a permit, pass, or visa to stay long term... even if you marry a local. The bright side is, if you marry a Sarawakian bumi, your children will be bumi.