I had seen this estate and house tour on a French tv show (Secret d'histoire) which is why I knew I could visit it.
It took us a few minutes to figure out the audio-guides but one we did, we were glad we had them. We did enjoy the slave quarters and other historic houses on site, as well as the tomb of Washington and his family. The grounds were well kept, with a nice view, and easy to walk around on well maintained path.
Parking was easy to find, free and I like that the stores were all grouped together for shopping at the end. We did have lunch at Mount Vernon's Inn, which had a great combo price-quality for a touristic place. My shrimp roll was tasty as was hubby's chicken and waffles.
The house tour was dissapointing. Although we had reserved a time when purchasing our ticket, we were to line up behind school groups for about 20 minutes before we got access. As it was towards end of day (3:30 I think when last tour was at 4:30), all guides seemed to be totally exhausted. Of course, it was abnormally warm for that time of year, but still. Spoke to a first guide in line which just pointed to where we needed to line up. Before we 'crossed' the street to line up again by the house, the guide spoke at length to the tour group before us, but nothing for us, she moved instead on to talk to a colleague. Having known that, I would have moved forward to listen in to what she was saying to the school kids. Then by the house before we went in, the guide there was in a foul mood and actually swore at someone that was filling their water bottle. Then we were herded in by huge groups, could barely hear what the guide was saying - in any case, she wasn't saying much; or didn't know the answers to basic questions people were asking. While we knew not all of the house was to be open, I would have appreciated a good tour, well narrated and made to feel like like history is fun.
Would not recommend.