Are these ok?

He likes galloping horses.

1. He gallops in the morning when the horses are rested.

2. He likes to come to the ranch to gallop horse.

That's a good start. :-)

But -- instead of your second sentence -- you could say --

He likes to come to the ranch to watch the galloping horses.

Yes, both sentences are grammatically correct. However, there are a few minor adjustments that can be made to improve the clarity:

1. He gallops in the morning when the horses are well-rested.
- This sentence indicates that he prefers to gallop in the morning, specifically when the horses are well-rested.

2. He likes to come to the ranch to gallop horses.
- In this sentence, the phrase "to gallop horse" should be corrected to "to gallop horses" to ensure proper subject-verb agreement.

Overall, the meaning of both sentences is clear and they are grammatically acceptable with the suggested adjustments.