[John Webb]

You need a section of baseboard which can be moved out of the way. This can be done two ways:
(1) A section hinged at one end - you lift the other end to raise the section to the vertical and open the way to the door;
(2) A section which lifts out completely to provide access to the door.

A number of books describe how to do either of these methods - look in your local library. One book that may possibly help is the 'PSL complete guide to Model Railways' edited by Michael Andress - but I cannot find my copy to check for certain.
Regards,
John Webb

 

[John Webb]

If a lift-out board, then connectors each end to link the tracks together will be needed. If a hinged section, then you may be able to have a flexible but permanent connection at the hinge end - but a plug and socket at the opening end will also help ensure continuity round the layout.

I regret the PSL book mentioned in my post #3 does not have anything on removable sections - sorry!
Regards,
John Webb