Hi -- It sounds like you've taken the right approach to these sections of your project. Your conclusion should, yes, be a summary of your project and the results you observed -- and how you proved or disproved your hypothesis.
Have you looked at this page from the Project Guide: http://www.sciencebuddies.org/science-fair-projects/project_conclusions.shtml?from=AAE
It may help as it contains a list of the key elements of the conclusion, some samples, and a checklist.
For your display board, you'll want your conclusion listed. If you have elements from your longer discussion that you want to highlight for the viewer, you might add some of those in a list. But you don't want to put the entire text on the board. You could make that available in a log book, possibly.
There is a useful diagram on this page which shows a sample layout for a Project Display Board:http://www.sciencebuddies.org/science-fair-projects/project_display_board.shtml?from=AAE
Also, we posted a blog piece on Project Display Boards last week that you may find useful:http://www.sciencebuddies.org/blog/2012/03/perfecting-the-project-display-board.php?from=AAE
As for fonts... keep the font in mind! It makes a difference. http://www.sciencebuddies.org/science-fair-projects/project_display_board_fonts.shtml?from=AAE
Good luck with your project!