Will not start

Recently purchased 85 300DT with 114K miles. Car sat up for ~ 1.5 years prior to purchase. Bought new battery and added fuel. Drove for ~ 300 miles over a period of several days and then added fuel additive and filled the tank. Drove another 50 miles the next day. She drove perfectly. Got up the next morning (temp 30 degrees) and she would not start. Haven't been able to start since. Noticed the manual fuel primer pump appears to be in the UP position. Any ideas on why she will not start? Visual of fuel in pre-filter shows little to no sludge. Any help appreciated.