What about http://www.mangago.zone/read-manga/saver/ ?
It's not comedy and is more on the serious side but I thought it was good. (I just noticed its josei but I still recommend it >_<)
http://www.mangago.zone/read-manga/shinobi_life/
^This one is backwards of red river. The male character time travels to the future and meets the heroine.
That's pretty much all I've got with shoujo/josei time travelling. I also really like http://www.mangago.zone/read-manga/7_seeds/ . The characters wake up no one knows how many years after an apocalyptic event. Not sure if you're okay with this type of time travel.
And I know this next manga doesnt have time travel at all, but I really felt like recommending it. http://www.mangago.zone/read-manga/basara/ is actually set in a futuristic japan (although it seems more like past than future). It has a very mature storyline but its not comedy. Its very beautiful though in my opinion.
so ok, my timetravel collection is not yet completed (since i have not marked a large percentage of straight manga's i've read) but you might want to take a look. just refer to my reviews http://www.mangago.zone/home/mangalist/93004/
Can I recommend some for you to add? :D
Hi, could you please recommend some good shoujo manga with time travel format like Red river, but with a bit more mature storyline and still funny. Thank you very much and love you guys XD