Regarding "tedious" math:
Not sure how exact you want to be, but a quick conversion is 5lbs grain to 4lbs LME or 5 lbs grain to 3lbs DME. I didn't open the link Union mentioned above, but iirc it shows basically the same values. Probably some rounding errors though.
On the other hand, I'm really good at doing math in my head. If you aren't, what he mentioned is a good lookup table. If you had something more exact (like 43ppg for a grain vs 44ppg) you'll either have to accept the error or do the tedious math.
Edit: regarding the actual question - yeah, pilsner or two row would be good. Or mix the two. And if you really want to follow the recipe exactly, let us know the maltster. Someone can probably let you know a rough breakdown of base malt to crystal included in the extract.