I live in the UK now, but moved here from Hawaii, having lived there for 20 years. I did not have horses in Hawaii, but did own land on Oahu and the Big Island. We owned a home in a residential area of Oahu, called Kailua. It was on 1/4 acre and was a street and a half from the beach. We also owned 30 acres on the Big Island, in an area called Volcano. We never lived there, but rented out a very small cottage on the land. Both of our properties were owned outright, otherwise referred to as fee simple, as opposed to leasehold (and neither me nor my husband contain a drop of Hawaiian blood).
I was very involved in the dog fancy during my time in Hawaii. When we moved to the UK, I brought with me 15 dogs (6 Golden Retrievers and 9 Norwich Terriers). They had to go through 6 months of quarantine in the UK.
There are areas on the Big Island that are not unlike some parts of the UK. The area of Kohala is very green and lush, with major cattle ranches and horse farms.
The higher the elevation, the cooler the environment. It is true that everything is imported from the Mainland, so prices are higher.
PM me if you wish. I lived on the Big Island for 2 yrs, had my horses shipped by boat to Oahu. I would personally not want to live in Puna or Mountain View. Have you visited to check out the various areas as they vary tremendously? If it seems like a deal it's probably mostly lava.....
There are some lovely areas on the big island and other areas that for me were downright depressing (nothing but lava rock), pretty much anything much south of Captain Cook. Hilo side can be wet but much nicer than the southern part of the island and cheaper than the Kona side and northern end.
Horse country is more in the Waimea region (paniolo country) and Kohala, very pretty. Pretty much any area that is suitable for horses is going to be pricey, I looked at tons!
And yes watch out for land leases (Bishop Estates). Most times when you find acreage that's not a fortune it's because it's on a land lease and the houses can be total shacks. And catchment tanks are the norm.
Lots of nice coffee farms and macadamia farms! My husband is still ticked we didn't buy a coffee farm LOL.
Most grocery stores have kama'aina cards for residents, which gets you cheaper groceries than the tourists pay (sometimes MUCH cheaper).
For me there I couldn't live with the lack of hunter/jumper stuff. It was fun while it lasted and I do miss it but couldn't come to terms with no more horse shows etc. I did used to swim with wild dolphins virtually every day in Kealakekua Bay and I sure do miss that!!
Much of Puna's in the line of fire, make sure that the land you're looking at isn't going to be buried in lava. Mountain View is close to Hilo, and therefore probably safe. It will be "old Hawaii" though, think more along the lines of burly Polynesians in rusted pick up trucks and less along the lines of palm trees and coconut drinks. Personally, that's what I prefer. But a lot of people think I'm nuts for that.
My sister lives in Hilo and has had a farm for years. She currently has goats, chickens, a donkey and a few mini's but has had horses in the past. She owns her land (no lease issue), I think it's around 30 acres. She feeds cubes and all stock to the goats and horses. In hilo, getting a ggod vet always seems to be an issue, the closest is in Waimia (or whatever its called - its on the top of the road from hilo to the kona side). Her biggest issue with the horses was hoof absesses. I was thinking of re-locating a few years ago - lived in colorado at the time, board prices were similar. Shows are few and far between, but I found at least one nice dressage barn - there is also a nice small place that does dressage near kapoho. The fair grounds in Hilo board for a very reasonable price, but it's self care. When I looked into it, there wasn't a problem in terms of the horses that stopped me. We even bought 6 acres outside of Hilo. We never moved because I would have been too far from my other family - my adult children. Work would have also been an issue, but at the time, not a big concern for us. If you need an income, that will be a bigger problem, I think - there aren't alot of jobs. And everything is definitely more expensive. but if you don't have family keeping you on the mainland - I say go for it!!! Its a wonderful life and the people are awesome.