A few well-placed trees or shrubs can make a world of difference. In many cases the facilities department can handle some of what has to be done, or you can contract out. Be aware that there are costs for these services that can sometimes be a surprise to many administrators. Of course, most mobile space providers also will be able to handle the installation for you. This is a cost you will incur only once, unless you later choose to move your space to another site.
Some providers offer turnkey service.
In other words those providers can arrange everything to do with the installation, from obtaining permits to building an entrance ramp. All you do is place an order and on the appointed day, start holding classes. But other considerations are experience in constructing classrooms in your state, and in-plant inspection by the state architect's office. Another often overlooked concern is whether the supplier is bondable and approvable. Also, you want a provider who understands what you need and will work with you to make sure you get it.