czasy przeszłe

Then one afternoon, while we were resting (rest) at the top of a valley, we noticed (notice) that a rider on a horse was waving (wave) at us from the other side of the valley. A rider whose clothes were shining(shine) like gold!
czy dobrze uzupełniłem?

ok

he believed (believe) that the descendants of these ancient people still kept (still keep) themselves apart from the rest of mankind for the very same reasons. So when we set off(set off) on a cool May morning towards the distant mountains, each of us were looking forward (look forward) to exciting discoveries.

jeszcze nie jestem pewny, co do look forward

each ... was