golden week/tokyo disney sea

Thank you so much for everyone who has responded to my questions.
We would like to go to Disney sea on April 26th or 27th. Golden week doesn't officially start until the 29th. Do you think we will experince more or less crowds either one of those days?
I also read that traffic leaving major urban areas will peak on May 2nd. Does that mean that passenger travel on trains going into Tokyo will be less crowded on the 2nd? Any help would be appreciated. Thanks..

We would like to go to Disney sea on April 26th or 27th. Do you think we will experince more or less crowds either one of those days?

Sundays are considerably more crowded than Mondays!

I also read that traffic leaving major urban areas will peak on May 2nd. Does that mean that passenger travel on trains going into Tokyo will be less crowded on the 2nd?

Depends on the route. If it is a major intercity route, it will also be crowded, but less crowded than trains leaving Tokyo. If it is a minor route coming into Tokyo the countryside, it probably won't be very crowded.

Going to Disneysea on 27th. April will be better,since always Monday is less jammed than Sunday.

Jam of 26th will be the same like as other Sundays of April,of 27th will be also same as other Mondays of April.
Disneysea will not so jammed on 27th.that you will be able to enjoy it,however it will be much more jammed than winter time.
(Winter is the most empty season for Disney Resort.)
Disneyland will be heavy jammed on 26th,however jam of Disneysea will be acceptable,Disneysea is always less jammed than Disneyland.

Even if the road is not congested,never go to Disney Resort on 2th.May,they are drastically jammed!
Admission will be restricted on 2th.May, due to too much guests.