It's easy to document your trip for later scrapbooking by taking a mini journal with you.  You can document your day to day travel for later scrapbooking.  Using a map makes a great and unique background to your scrapbook.
I usually spend the time during the trip gathering materials and then I do a big session after I get home.
In lieu of keeping a written journal on your trip, take informative photos.  They and memorabilia can help you remember details when making the scrapbook.
Yeah my scrapbooking is a little less detailed. I don't have trouble remembering what I did on the trip.
You can also assemble a digital scrapbook while traveling by uploading photos and reminders as you go.  It can be fully customized and easy to assemble and save time making a paper scrapbook.  
I have my method and I love my paper scrapbooks. Do you like to travel?
Traveling can be a much needed escape for relaxing.  Have you ever valuated any of the postcards you've collected?  Some older, or rare postcards can hold significant value depending on the age and topic.
No none of them are old and rare. They are all the modern kind you buy at a souvenir shop.
An elongated or pressed penny is a great souvenir as well, and more durable than a postcard.  They are avail in most travel destinations.  Books are available to display them.
I'll look into that. Why are you giving me so many suggestions to change my methods?
Creativity leads to better imagination and originality, it helps make everything you do better! 
Thanks for the tips. I'll consider them.