到山上游玩一天: go on/make a day excursion to the mountains ie there and back in one day
跟上: keep pace with; catch [keep] up with; keep [be] abreast of [with]: 跟上时代的步伐 keep pace with the times; 跟上科学上的最新发展 keep up with the latest development in science; 跟上形势 keep abreast of the cur
