Travel during National Holidays?

Hi All.
I will visit Japan in September. Two National Holidays will happen during my visit: "Respect for the Aged Day (keiro no hi)" and "Autumn Equinox Day (shubun no hi)". My question is "What is the best choose to do during those Holidays:
- To stay in the big City?
- To travel between cities?
- Does public transportation will very busy, during those days? Is it possible to make advance booking for those days?
- What about "luggage delivery" service during the Holidays, is it working as regular?

Thanks in advance

Nothing much changes for those holidays. Everything operates as normal.

I have been in Japan for those holidays and have always been surprised how they seem just like any other day. A few museums etc may be shut the next day to make up for it. You might notice more Chinese tourists as the Autumn equinox seems a popular time for holidays with them.
So, no need to make special plans.