Question about Huawei E5573

In principle, it will already work in the USA and Canada.
The problem, however, is that the E5573 lacks the LTE frequency bands 12, 13 and 17 - these are the frequencies in the 700 Mhz range. 700 Mhz is used in the USA and Canada for the basic LTE coverage of the large providers in the area, i.e. it is the main frequency.
So it might look bad "in the country" with reception if only 700 Mhz LTE is covered with the E5573. In the cities, however, additional frequencies are used which the E5573 supports in order to increase the capacity of the LTE network.
So it could be that LTE reception is possible in (larger) cities and not in the countryside - not really ideal.

I would make sure to buy a device that supports the 700 Mhz band so that you can be online everywhere. Why not buy it locally together with a sim card?