My Stepfather's 1986 VW Golf Diesel got 50MPG, and would get you there ...eventually. It still got 50MPG in 2003 when it had to be driven to the junkyard. It would no longer pass safety regs in MA, and it would be prohibitively expensive to fix.
His 2002 Golf TDI gets 50MPG and produces 2x the HP and 3x the torque, or so it feels. The only downside I've observed thusfar is the turbos needing to be cleaned and/or replaced. I'd be in the market for a VW diesel myself, but idiot MasNoNoNoNoNoNosetts doesn't allow the sale of diesel passenger cars anymore.