Climbing roses can get quite large, and I think yours will outgrow those little trellises quickly. If you google images of climbing roses, you will see most of them supported by sturdy wooden or metal posts in a variety of designs. I've seen roses grown on sturdy vertical posts with chains or very heavy rope suspended in swags between the posts, which might be a good solution for you. I couldn't find a picture of it. You can make taller trellis supports out of long pieces of rebar from the building supply, bent into the shape you want. Check the rose forum for more suggestions. Here's a simple narrow pergola, maybe a version of this would work for you? Here is a link that might be useful:

For a big pink rose blossoms with fantastic re-bloom I would grow 'Susan Louise' as of April 5, 2013 it is available from vintagegardens.com The blooms are a bit bigger than a tea saucer on a mature sized plant, and are pink and cream. The outer petals are a more saturated pink which gives interest to the blossom. Here in the San Francisco Bay area 'Susan Louise' is one of the most disease resistant of all roses, and never needs spraying. I would not put jackmanni with it on a regular sized arbor, as the rosebush is large enough, but if I wanted to see purple and pink, in spring I'd plant fragrant purple sweet peas with it. I have never seen a photo that has done the plant and the bloom justice, it really is special, floriferous and blooms fully here in winter, as well in the other 3 seasons. Luxrosa

Before you get into the details of what to do, I would take a step back and look at the LOCATION where you want this rose to grow: 1) What region of the US are you in? This will affect what you can grow - do you have freezing winters? Do you have hot humid summers? Do you have hot dry summers?, etc. etc. Each situation is OK, but different situations call for different kinds of roses, and you want to get one that will like what you have to offer. 2) How much sun will this rose get per day? Since you say this is a Northern exposure, this is very important. Look at the location, both at the bottom where you will be planting the rose, and higher up where the trellis will be. Look at it in various times of day. Folks on here can be much more helpful after we know the answer to these questions. Re metal trellis - not good, as in any sort of sun at all it would get too hot and burn the rose canes. Looking forward to hearing more about your project. The short answer to your general question is, yes, you can do this - it is not difficult. It is just important to choose a rose that will cooperate with you and where you are and where the garage is. Jackie

When planted in the ground and established, it will make 8'-10' shoots from the base that will bypass the paltry first year growth, so it doesn't matter what you do with the extant stems--except don't prune too much and waste stored energy. This is a huge rose unsuited to pot culture, so I would try to decide where to put it and plant in the ground right now, before it leafs out.