Re question on work permits:
You would require to obtain a work permit to allow you to enter Canada to work in the field you indicated.
How hard is it? First of all, you would require to obtain a valid job offer from a potential employer. That employer would then have to submit an application to Human Resources Development Canada (HRDC) and satisfy them why they are seeking to bring in a 'foreign national' to fill a job vacancy. HRDC would then provide a labour market opinion or 'confirmation' for the offer. If you, as the potential employee meet the set criteria for the confirmed position, you then may apply to Immmigration Canada for a work permit . As a US citz, you may apply at a port of entry. Note there is a fee of $150.00 Canadian for the permit. You will also have to meet the general requirement of the Canadian Immigration and Refugee Protection Act (IRPA) to gain entry to Canada - this basically means no criminal records and no health issues.
It's not as hard as it sounds, the employer (if they really want you) will do most of the work. For more info on working in Canada, check out this site:
www.cic.gc.ca
Hope this answers you question.