I'm going to England on holiday!

Dear George!
How are you? I'm fine. The Next month I'm going to England on holiday, I read an article about Arundel Castle and I would like to visit this building.

I'm planning the route; On the one hand, I will go at 10am to visit the church and the grounds around the castle.

On the other hand, at 12am, I'd like to go to see the main castle rooms, these rooms have to be very interesting.

Finally, I want to have a lunch in the restaurant,. Maybe, after the lunch I'll go to the castle shop.
I'm pretty excited for known this building, because I like the architecture, and furthermore, inside it I can see the paintings  I can even see fascinating furniture; For these reasons, I think that I will enjoy it very much. 

Do you want come with me? Whether you want to or not, after the visit we can go to drink a beer or not.

'on one/the other hand' should only be used for alternatives, or contrasts.

Lunch is normally uncountable (although it can be countable)

'for known' is not a good phrase here. You need something else. Perhaps 'to have the opportunity to get to know', or just 'to visit'.