If the negative contains all the information, i.e. shadow details are there, only a bit thin, then it will be possible to print. In my experience, a darkroom print always comes out better than the best scan one can do with desktop scanners. I don't have experience of drum scanners, so I won't go there. But my darkroom prints are better than anything I have done with my Minolta Dimage Pro and my father's Epson V750. So my take is: If you can scan it, you can print it. I have not even used grades as high as 5, maybe 4 max. It is more an issue of getting the exposure right, because a thin negative will give a way shorter paper exposure than a normally developed one. In any event, I think the published guidelines err on the side of a slightly denser negative than is necessary for 35 mm, seeing that the larger formats can bear quite a bit of extra development without grain becoming an issue. An over-developed 35 mm negative may show significantly more grain than a slightly under-developed one, even on slow or medium-speed film. So it is not a bad idea to practice slightly shorter developing times for the same film in 35 mm compared to 120 or larger. The one thing I find challenging printing thin negs on my own setup is that the short exposure gives me very little time to do dodging and burning. One may use ND filters, but I haven't got one that fits the lens thread, and haven't gotten round to getting a stepping ring.

Another possible recourse is to intensify the negative. I have not tried this myself. However, Tim Rudman gives good guidelines in his "Master Printing Course". His intensifier of choice is mercuric chloride, if I recall correctly. It is a chemical that I have not been able to obtain, for reasons probably related to its toxicity. There are other methods too. You may consider taking more than one frame where possible, so that if one negative is ruined by intensification, you at least have something to fall back upon. You may also consider exposure bracketing, so that you have negatives of different density for scanning and printing purposes. This will work with landscapes and such, but probably not for unposed people & street photography etc.