score:6
According to the Verizon Trip Planer they don't offer LTE roaming to Germany for all devices I checked. You can use that tool to look up coverage and plans based on your devices.
Even if this were working, the plans seem more expensive than what you can get in Germany. All networks now provide LTE coverage but you need an unlocked device which works with the German frequencies (this data can be looked up if searching for the device's data sheet β most LTE devices sold in recent years should work). The frequencies are 800 MHz, 1800 MHz, 2100 MHz, and 2600 MHz but not all networks use all of those frequencies everywhere. Alternatively you can get a cheap LTE data stick for your laptop in Germany when getting a plan.
You can check coverage for the networks on their maps (order based on my personal experience from best to worst):
The last two just started to combine their UMTS networks but you can't use the other's LTE network.
Those networks also offer their data services through a variety of resellers. However, almost all specifically exclude LTE.
Only prepaid services seem reasonable for your use case. The only such service that offers LTE I know of is Vodafone CallYa.
Also all E-Plus prepaid plans include LTE up until the end of the year. Some of the more popular are
For some but not all customers (including me) LTE works at Congstar (Telekom network).
You should be able to get those Prepaid SIM cards in some German shops but the availability differs depending on the specific offer. This is easier than getting them via postal service.
Those are all real LTE services. I think in the US they market HSPA+ (with up to 42 MBit/s down) also as LTE. That is much more readily available in Germany but I have not much knowledge about that.