It is a rewarding journey.
这是一次收获之旅（言简意赅）.（或,这是一次收获颇丰的旅行.）
1.We have with us at the reception…
这句话的意思根据我的理解应该是：参加本次招待会的有…（罗列人名）
2.Allow me, first of all, to express our cordial welcome to our distinguished guests.
译：首先,请允许我向各位尊贵的客人表示热烈的欢迎!
3.It gives us great pleasure to entertain our distinguished guests here.
译：能在此招待各位,我们实感荣幸.
4.Renew our old friendship.
重续旧日友谊.
5.Comments are welcome./Your advice will be appreciated.
我们欢迎您的批评、指教.
6.Do you still feel the jet lag?
您时差倒过来了吗?（jet lag - 时差症：由于在喷气飞机上快速跨越几个时区而造成的短暂的身体节律的紊乱）
7.Today we gather here to solemnly commemorate…
今天,我们齐聚这里,隆重地纪念…
8.Your presence just honors this meeting.
您能出席这次会议,我们倍感荣幸.
9.On behalf of all my colleagues, I would like to extend our warm welcome to you.
我代表所有的同事,向你表示最热烈的欢迎.
10.With a sense of great sorrow we bid farewell to…
怀着沉痛的心情,我们向…道别（或者根据后文,译作：我们告别了…）.
11.Let us toast to our long-standing/time-honored friendship.
让我们举杯,祝愿我们的友谊地久天长!（或者口语化一点：愿我们的友谊地久天长,干杯!）
12.We go back with a full load of friendship.
带着友谊与祝福,我们满载而归.（稍微意译了一些,毕竟意译也是翻译的技巧之一嘛）
手工翻译~