How to travel from Paris to small village in Picardie without rail service or rental car

I would ask this on tripadvisor.com paris forums .. the locals there are super helpful with this sort of question.. I had to do similar.. travel to a tiny place,, no rail or car. So they told me the two closest places to get train to.. and from one I could walk ( about 2 kms ) to village.. and from other I "might" be able to take taxi .. but could take a local bus.. its definitely worth asking someone that lives there.

Looks like closest town with train station may be Le Plessis-Belleville.. do you have a friend or family that can meet you ?

According to RometoRio.com from the train station in Le Plessis-Belleville to Lagny-le-Sec is a 4 min taxi ride or a 1/2 hr walk. So that may be your best option. I believe you could hire a taxi to take you there from Paris but it will be quite a bit more expensive.

Isn´t there somebody in Lagny-le-Sec who can help you?

If not I would check again about trains. According to me Le Plessis-Belleville has a stop on Line K between Gare du Nord and Crépy-en-Valois. Have no experience, but worth a closer look before thinking about an expensive taxi. You can also thinking about RER-B to Mitry-Claye (close to Mitry-Mory, near CDG) or the branche to CDG and arranging a taxi from these places.

Here are some websites we've been consulting, so you can look for yourself:
https://www.rome2rio.com/ Use this to find Paris-Le Plessis Bellevill.
http://www.viamichelin.com/ Use this to see the distance from Le Plessis Bellevill to Lagny-le-Sec.
Use an on-line converter to change the kilometer to miles.

It's 1.6 kilometers, or one mile, from Le Plessis Bellevill to Lagny-le-Sec--nothing--unless you have health issues or are carrying a heavy object. So essentially, there is both a train and an RER to Lagny-le-Sec. You are in luck.

Bets – As far as I know the final stop on RER-B is Mitry-Claye, however on the same line to the further located Le Plessis-Belleville, but for going to there named “Ligne K” (with final stop Crépy-en-Valois). Or do I miss the latest info?

Here are the SNCF results for Paris to Le Plessis-Bellevill:

http://www.sncf.com/fr/itineraire/resultats

And Google maps confirms that Lagney-le-Sec is 1.6 kilometers, or a twenty minute walk, from the station. Use google maps putting in Le Plessis-Belleville gare and Lagney-le-Sec into the directions boxes.

I did some searching on the local bus site and there is a very limited bus service to Lagny-le-Sec from Senlis railway station. The timetable is at this page. Note that the service is different on Wednesday (Mercredi) to other weekdays. The journeys with the green "FLEXO" indicate that the bus serves those destinations only if people who board during the early part of the journey request it. The bus does take over an hour, so walking or taxi from the other station may be more convenient.

Helloooo anyone there..

Oh Pat, you made me laugh. I was just wondering if the OP had gotten back to thank us and then saw your post. Thanks for making my morning.

My sincere thanks to everyone who posted suggestions and advise for travel to Lagny-le-Sec. We now have several options. Your kind assistance is greatly appreciated.
Beki