I hope these fit what you are looking for!

Once Upon a Time (http://mgbutterfly.livejournal.com/154997.html)
Summary: Dean is a bitchy thirteen-year-old. Sam wants a bed time story. Sam should know better than to ask Dean.

Backseat Drivers (http://wanttobeatree.livejournal.com/410247.html)
Summary: Here's some wee!chesters in a traffic jam.

Dead Bodies (http://chaletian.livejournal.com/183623.html)
Summary: You just know John had to come up with ways to keep Dean and Sam occupied…

Thank you :)

It's short, but this fits what your looking for I think

Backseat Living (http://archiveofourown.org/works/2151582) Sam and Dean rarely ever fight. But good god, do they bicker.

That was great! Thanks for the rec!

kellyofsmeg writes some great wee!chester fics. These two are my favorites:

https://www.fanfiction.net/s/9719789/1/Normalcy (https://www.fanfiction.net/s/9719789/1/Normalcy)
Summary: In between hunts, the Winchester family gets to have an ordinary day at the park. Short & fluffy Weechester! and Papa Winchester goodness.

https://www.fanfiction.net/s/9686424/1/Thank-You-Gideon (https://www.fanfiction.net/s/9686424/1/Thank-You-Gideon)
Summary: Sam and Dean are left in a motel room on a hot summer today, and get an unwelcome and pesky visitor.

Hope you like!
Illyria

those were great! thank you!

I've self-reecced these before, but I'll do it again and hope you like them.

More Than Meets the Eye (http://archiveofourown.org/works/864925)-John leaves his sons with Bobby for the summer while he continues to search for the thing that took his Mary from them. Adorableness transpires. Dean is awesome…and Bobby’s pretty good at it too. (Need familiarity with 6.17 “My Heart Will Go On” as fic is set in AU world made canon in that episode.)

Warnings: none beyond unadulterated schmoop; also some h/c and angst, sick!Sammy
Characters: 9-yr-old Dean, 5-yr-old Sam, Bobby, John and others

Captain Awesome Big Brother and the Boring Motel room of Doom (http://archiveofourown.org/works/865435)-Wee!chesters - Bored banter. The boys are bored, stuck inside, the TV is broken and Dad won't be home for at least two more days.

Characters: Eight yr. old Dean, aka “Captain Awesome Big Brother” and 4 yr. old Sammy, aka, (according to Dean) “Bored, bratty, pain-in-the-ass little brother.” John is mentioned.

Thanks very much! I had read the second one before. So cute!

On Duty by Weesta
https://www.fanfiction.net/s/3076415/1/On-Duty

This story is one of my favorites. John's doing research while watching Sam and Dean play on the beach.

that was a great read! thank you!