What is the ruling on a traveler praying before its prescribed time, and is it permissible for him to shorten it, and how does he make up for prayers during his travel between two cities, and how does he make up for missed prayers after his return?

It appears that you will not stay for four full days, excluding the days of arrival and departure. Therefore, it is permissible for you to shorten and combine prayers until you return.

Regarding combining two prayers by performing them early during the time of the first prayer, this is permissible for you while traveling. Similarly, delaying them and combining them during the time of the second prayer is also permissible. However, performing a prayer before its appointed time is not valid.

You must maintain prayer at its appointed time. If you miss some prayers, you must make up all missed prayers immediately while traveling, and they should be shortened. If you make them up after returning from your journey, it is preferable to make them up in full.