At 45° Latitude you will want the panels sloped at the Latitude plus 23° in the summer, and minus 23° winter; and pointed square to the mid-point of your sunshine allotment, where usually it is point them due south you will want to maximize the actual sun 'window' as is presented by the site.
Remember a solar panel actually appears as a huge "STEAL ME" banner to a certain segment of the population so not only will the mountings need to be sturdy with Lake Huron weather possible it also is recommended to be stowable or removable for when it is to be unattended for any extended length.
If there is a better sun spot nearby (10-15 meters maximum) having it placed there and thicker copper wiring would be worth the work to avoid visits up on the roof and less hassle since it will be easier to access to stow it away.
Now - as to size of panels it comes down to what's your budget, expect to pay $5USD plus per watt retail, and think modular so when its time to add more a duplicate panel is readily available.
For your purposes a non-UL listed House brand "SUN" panel from Solar Panels : Solar Panels under $3 per watt Worlds Lowest Price, Buy Solar Panels at Sun Electronics, When the power goes down, the Sun comes up!
is probably the most economical even after shipping, (Do you know someone in the states to accept delivery and you hand carry it back?) AND their panel price is the lowest I've ever seen, yet the biggest plus is you can choose their "Sunpower" cells house-brand that use the highest efficiency cells on the market for more power per M²...
And to cribbing up a trailer - http://www.airforums.com/forums/f457...tml#post419224
is how I accomplished it safely...