I'd like you to check the following sentences on a description of a journey. Thank you.

1) On my last summer holiday I stayed in a hotel at the seaside.
2)The hotel was very luxurious with an indoor- and an outdoor-swimmingpools., a sauna and a pizzeria.
3) It overlooked the beach and it was very convenient since it lay near the beach.
4) While I went sightseeing, I visited the cathedral. Then I went on a boat sightseeing tour of Venice and of (?) a little island called The island of the shells.
5) As I live in a small town, this trip showed me that there is a big world outside.
6) The journey by (on?) car was very boring, so we spent time listening to music on earphones. My dad drove and we never went the wrong way.
7) Sometimes we stopped for gas and we went out to buy souvenirs.
We stayed in a four-bedded room which wa ver clean and big wiht a shining bathroom and two fantastic armachairs.
8) The hotel was a full-board (Better: we were in full-board.

1. comma needed

2. "... with indoor and outdoor swimming pools, a sauna, and ... "

3. comma needed

4. "...on a boat for a sightseeing tour of Venice and a little island called The Island of the Shells."

5. OK

6. by (not on)

7. comma needed

We stayed in a room four four which was very clean and large, with a shining bathroom and two fantastic armchairs.

8. I don't know what "full-board" means.

Here are the revised sentences:

1) On my last summer holiday, I stayed in a hotel by the seaside.
2) The hotel was very luxurious, with both an indoor and an outdoor swimming pool, a sauna, and a pizzeria.
3) It had a beachfront location, which was very convenient.
4) During my sightseeing adventures, I visited the cathedral. I also went on a boat sightseeing tour of Venice and a little island called "The Island of the Shells."
5) Coming from a small town, this trip exposed me to the vastness of the world.
6) The car journey was quite monotonous, so we entertained ourselves by listening to music on our earphones. My dad drove, and we never got lost.
7) Occasionally, we stopped to refuel and took the opportunity to buy souvenirs.
We stayed in a four-bedded room, which was very clean and spacious. The bathroom was sparkling, and there were two fantastic armchairs.
8) We opted for full board during our stay at the hotel.