I don't know when I have had such a delightful(pleasant)(memorable)(enjoyable)weekend as the one...
我不记得曾否有另外的一次像那次高兴的（愉快的）（难忘的）（快乐的）度过周末。

This is to thank you again for your wonderful hospitality and to tell you how much I enjoyed seeing you again.
再次感谢您的盛情款待，并希望再见到您。

Thank you for one of the most enjoyable visits we have had in many months.
在您处的参观访问，是我们几个月中最愉快的一次。谨向您表示感谢。

Thank you for one of the most memorable days of my trip.
为了旅途中最值得留念的一天，谨向您表示感谢。

Thank you for one of the most enjoyable visits we have had in many months.
在您处的参观访问，是我们几个月中最愉快的一次。谨向您表示感谢。

Thank you for one of the most memorable days of my trip.
为了旅途中最值得留念的一天，谨向您表示感谢。

Thank you for doing so much to make my trip to New York interesting (pleasant)(resultful).
为了使我去纽约的旅游有趣（愉快）（大有收获），您做了许多事，特此致谢.

Thank you for contributing so much to the pleasure of our stay in ...
感谢您为使我们在……的停留期间的愉快所作的许多努力。

Thank you so much for your generous hospitality.
非常感谢您慷慨的款待。

I hope something will bring you to New York soon so that I can reciprocate your kindness.
希望不久您能有机会到纽约来，使我能答谢您的盛情。

You must give me the chance to return your kindness when you visit here.
希望您光临我处，使我能答谢您的盛情。

来源 http://www.translator.com.cn/content/garden/garden.asp?kind=AJ