Do an advanced search for the posts by toyman. He lays out the time and costs for a first class restoration. Walt is a well known restorer and has recently completed an excellent Mark II restoration. Barry Wolk also shows some nice details of a restoration but he doesn't give much man-hour and cost details.
There is a huge difference in resale value when you look across the spectrum of Mark II restorations. A world class restoration will bring big dollars. In 2015 and 2016, the highest Mark II cars have sold for approximately $250K and $330K, respectively. However, these are extraordinary exceptions. A nice "restoration" would probably bring around $60-75K. All of these numbers are rough estimates based on existing auction results.
1956 Mark II C5601429
1962 RR Silver Cloud II drophead
2006 Ford F150
2010 RR Phantom drophead
2013 Maserati Gran Turismo drophead
2015 Lincoln MKT