That would not be possible because it has become basically impossible to bring in vehicles close to 5-10 kms of the front-lines because of the, well, drones. And you need to carry ammunition to those mortars with something, preferably not how the Vietnamese did it in the jungle (i.e. using brute human force).
Just check this snippet from a recent article in the FT:
> “'At this point, you’re a lucky man if you drive 5km from the front line and your car is still operational,' a Ukrainian drone unit commander deployed in eastern Donetsk region told the Financial Times. He said his men now sometimes had to walk up to 15km at night to reach their positions...
> In the past weeks, Ukrainian supply trucks have reportedly been hit by Russian drones on the road linking Kramatorsk to Dobropillia, some 30km from the fighting. On both sides of the front line, roads are being covered with anti-drone nets in an attempt to stop fibre optic drones."
This comes from Ukrainian guys still fighting this war, not from a Western war-tourist like the guy who wrote this article.