I'll assume you're taking the entire tuber clump, not simply a single tuber from the clump.

I would suggest you have the stem cut 2 weeks before you pick up the clump, and leave the clump in the ground during that time. That will let eyes form on the individual tubers so you can separate them.

3.5 hours shouldn't do anything to the clump. Probably best to hose it off before you transport, no need to bring any pests in the soil to your place. Place it in a bucket to avoid having tubers break off. Be sure to be careful with any visible eyes.

As far as storing goes, I used the "Saran Method" and it worked great for me (no tubers rotted.) After separating the tubers, wrap each one fully in saran so no two tubers touch, fold the ends over, and seal with tape. Place in a dark cool place (I put mine in cloth grocery bags with newspaper over the top of the bag and put them in a spare fridge.)

Enjoy!

Cheers,
Russ

Here is a link that might be useful: Saran method - Finally got them to winter over! How did you do?

Donzi you will have no problem. You can store tubers in saw dust,peatmoss or like Russ in saran rap. Where do you keep your boat?

I read this post entirely differently than you gentlemen. It sounds to me like donzi may be cutting a single stem/flower and hoping it will root. I don't know an answer, but basic propagation info and photos are found at the link.

See the links at "Decision Time".

Here is a link that might be useful: propagating dahlias

If what you say is true poochella and I think you may be all he would have to do is store the cuttings in a cup of water to transport.