Hi. We flew in there several years ago only the once. At that time there was a bus that went from Beauvais airport into central Paris. We then took the RER to DLP. TO be honest it was a nightmare at the time trying to carry all the luggage, kids and pram etc...onto RER and we had to change lines as I seem to recall. If you have no kids or they are older it probably wouldn't be as bad. We ended up taking a taxi from DLP to Beauvais airport on way home. I seem to recall it cost about 65 euro or thereabouts but that was about 3 or 4 years ago. I would imagine with a map it would be fairly straightforward to hire a car and I don't think you would struggle too much to find DLP. I seem to recall the taxi ride mainly involved a lot of countryside driving with nice straight wide roads. Hope this helps a little.
