You can do it, although what it will be like in April, I dread to think.
I did the following route over 17 days in July:
Harwich -> Esbjerg (Denmark) -> SE Sweden Coast -> Stockholm -> Umea -> Lulea -> Rovaniemi (Finland) -> Kirkenes (Norway) -> Hammerfest -> Tromso -> Trondheim/Hell -> Sweden -> Germany -> Geneva
...so you ought to be able to make quite a big dent in your route if you invest sufficient planning; you will however be riding long hours, and will probably bash quite a lot of motorway to hit that time schedule.
By the sounds of it you're cutting across the bottom of the Baltic peninsula, so our routes won't overlap too much; so here's some general advice:
1) Get the Adventure Motorcycling Handbook by Chris Scott, and read it, if you've not done this sort of thing before; check expecially the section on "Carnets" in case they are applicable to your route.
2) Nip down to M&S and buy "Skiiing Baselayer" clothing to wear under your kit; basically they're stretchy nylon long-johns and they pack down small, but you will need it. In mid July I nearly froze in a sleetstorm crossing Saltfjellen southbound near the Arctic Cricle, so what it'll be like in April is anyone's guess. Multiple layers of fleecy stuff under your kit makes for much greater comfort, and better/safer riding.
3) Norwegian road surfaces suck. See the stills/videos at:
http://www.crypticide.com/users/alecm/albums/2005-vacation-videos/ The snowploughs destroy the surface so they only bother to put down cheap tarmac in the first place. Do not be surprised by the subsidence-caused 2" step-down in the road, just after a hairpin bend.
4) Norwegian police are charming and will apologise profusely while they fine you 300 quid for the awful sin of doing 62mph on a national highway. The speed limit is 50mph, and they don't have mercy, instead they blame it on the government, so watch that throttle.
5) Soused herring for breakfast, petrol station hotdogs for lunch. I recommend avoidnig the latter in favour of visiting a Co-op and buying your own food.
6) Avoid booze in Scandanavia; it costs the earth, and there are on-the-spot-breathalyser police patrols in Norway. Think "Puritan Nanny State". Save boozing for a day-off in Czech or Germany where they consider alcohol to be part of life, not a social ill.
The scenery is incredible, the water tastes great, barbequed moose tastes like really good steak, and reindeer like venison crossed with beef. Just make sure you're waterproof from head to toenail, have at least two spare sets of gloves, and lots of thin layers to wear so that nothing is exposed.
, Mark.
Liv.
