This was the first time (visiting). This was the first time (visiting).

"Visiting" can be added to make the sentence clearer.

The city felt bigger than I imagined. The city felt bigger than I imagined.

Many hotels and offices were under construction, and I found out that the urban area would extepand in the near future. Many hotels and offices were under construction, and I found out that the urban area would expand in the near future.

I sawmet friends who had been toattended my college as an exchange students, and they tookshowed me around there. I met friends who had attended my college as exchange students, and they showed me around.

When I had trouble gettingunderstanding the Thai language, they interpreted for me. When I had trouble understanding the Thai language, they interpreted for me.

Thanks to them, I thoroughly enjoyed the trip well. Thanks to them, I thoroughly enjoyed the trip.

"thoroughly enjoy" is more natural than "enjoy well"