kodi, if you are planning on getting married on the grounds of Emerald Lake Lodge, you will need to get permission from the lodge to use their grounds, or else risk being asked to move along. As they sell wedding and elopement packages, they're not likely to be too keen on weddings just popping up out of nowhere. (See http://www.crmr.com/emerald/weddings/ ) It is in a national park, but the lodge has a leasehold for that land so for all intents and purposes, it's like private land. Of course, if you are not on the hotel grounds, but elsewhere near the lake, they have no say about that. However, you have no way of ensuring "privacy" in a public place in the park - although of course most people will be respectful if there is a wedding taking place, there is no guarantee. If, for instance, you are standing near the lakeshore getting married, and someone wants to stand near you to snap a photo of the lake, there's nothing you can do to stop them ... they have as much right to be there as you.
I also looked on the Yoho NP website to try and find wedding information for you, but could not. Here is the page from Banff National Park - the regulations would be similar in Yoho, but I don't know if you need to apply:
pc.gc.ca/pn-np/ab/banff/activ/activ37.aspx I would suggest contacting Yoho NP for more information (there is a "contact us" page on their website www.pc.gc.ca/yoho ). Further to my comments above about privacy, note that when you plan on having a ceremony outdoors in the national parks, in most cases, you cannot reserve the space, it's first come, first served. Here in Jasper NP, one of the most popular spots for weddings, Pyramid Island, has an area with benches and a pavillion, and there can be three or four wedding parties lined up and waiting on some popular dates (such as Saturday afternoons on summer long weekends), as well as tourists just sitting there picnicking etc.. The local wedding officiants try to work together to avoid booking too many weddings there in too short a time period.
And yes, you can pick up your marriage license in Vancouver. I imagine you will have to have a BC marriage commissioner to perform the ceremony... Field and Golden are the two closest BC towns to Emerald Lake. (I am not sure if an Alberta marriage commissioner is permitted to do wedding ceremonies in BC... I doubt it.) I found the following list of three in Field and Golden: http://preview.tinyurl.com/7yfuq49 I'm sure they will know all the details of planning a wedding at Emerald Lake, and would suggest you contact and book one of them as soon as possible. (Just as an aside - I went to a wedding here in Jasper NP late in September last year; the marriage commissioner who married my friends is an acquaintance and I spoke with her for awhile after the ceremony. She told me that she was booked for 5 ceremonies that day, 4 of them at Pyramid Island, and that the other commissioners in Jasper were also all doing multiple ceremonies that same day.)
Edited: 9:56 pm, February 23, 2012