Translation from English to Spanish options

My question is for those of you who have translated multiple documents, what would you recommend and why? Am I missing any other alternative way to translate our materials?

Well, there are lots of ways that involve commercial services, and either human translators, or human editors correcting machine translation, but these are typically more expensive than DIYing the formatting on AI-driven translation. For some kinds of translation - especially relating to health, PHI, or regulatory compliance - there are really strong arguments against relying on AI. But I don't imagine that your small community college has these kinds of concerns.

One way you can estimate the scale of such concerns is this: you can ask yourself "What are the consequences of an incorrect translation?" Because the consequences scale, to a degree; "I didn't make the sale" isn't as bad as "The reader filed an accessibility lawsuit over it." Lawsuite are better, in the grand scheme, than "the reader was injured as a result of believing the incorrect translation." I just saw a Critical Error a few months ago, where the poorly trained AI confused the Chinese glyphs for weeks, months, and days. That doesn't sound that bad, but it was a childcare handbook describing the ages at which children could be left alone, and for how long. So, that particular incorrect translation could have resulted in the death of a child. The moral of my little story here is that you shouldn't skip the part where you hire an editor who already knows how to do post-MT review. 

So, I can absolutely make some suggestions if you're interested (20+ years in the language industry, have formatted billions of words in dozens of languages over those years), but my advice is likely to be right out of your budget. (For example, if I were given your job, I would absolutely get the best translations I could for the English documents I already had in my archive, and then I would use the new translations to build bilingual corpora. Then I would use that data to roll my own machine translation tool based off of the vetted corpora, and could apply that to all new projects henceforth. ) But how much volume are you looking at, here? How many words in your archives currently, and what is your projected volume of new translations? Those numbers will let you estimate your total cost per year, right? That will help you figure out which tool will likely be the most cost-effective. 

Well, as the Id-Extras Translate creator, obviously I second @James Gifford—NitroPress , but in any case, the entry price for Translate is very low ($15, which includes a $5 translation credit). So I would recommend giving it a test drive, and seeing if you're happy with the results.

You can include a custom dictionary and/or a glossary (which is like a dictionary, only smarter as it takes into account different grammatical constructions, whereas a dictionary is a strict replacement).

The big advantage with our Translate add-on is that all the formatting is kept intact in your InDesign file. It's like "Google Translate" for a web page, just for an InDesign document! I'm not sure if other systems make it quite as easy...

Coming soon, too, is the ability to add a paragraph or two of "context," to assist the translation. This is a new DeepL feature, and I hope to include it in our Translate add-on in the nearish future...

Not directly addressing your translation issue, but it's worth considering that subscription services (like Adobe's model, for example) usually mean continuous update, better customer support and problem resolution, never having to budget for irregular updates, etc. Since your need/workflow is continuous, I can't see a downside to a continuously "current" tool for it.

(It's much different when a need is one-shot or very infrequent, and then subscription tools can become a budgetary burden, especially for solo/small shops.)