Ancient Battlefields

[Vortexmind]

The only problem is that many of the battlefields might no longer remotely resemble how they were at the time.

You are right, for example there is a dispute about the exact place of the above mentioned battle because some people thinks that river Trebbia has changed his course due to sedimentary deposits over the centuries. Anyway, proof of the battle (weapons, helmets and so on) have been found in that area, which is also accounted quite precisely in Polybian Histories ... so I think it depends on the sources of information you can get.