It seems to be useful for the autumn holiday season! I found a cute picnic sheet at the 300 yen shop "MODA 300+'" and bought it.
A polypropylene picnic sheet that comes with a case that is convenient to carry. The size of the seat is about 60 x 90 cm, and it is a size that one adult can sit on and a bag etc. can be placed. It is not waterproof, so it is safe to avoid using it on bad weather. Also, since it is a material that is sensitive to heat, be careful when using fire such as campfires.
The price is 324 yen (tax included). Why don't you put it on standby at the entrance and take it out quickly when you go outdoors?