You can send a package to Abisko as long as you notify them well in advance. You will have to pick it up at Godisfabriken Supermarket in Abisko Östra, a bit east of the tourist centre. From STF Abisko page:
Ja, du kan skicka både brev och paket hit mot en mindre avgift men du måste, i god tid innan, kontakta receptionen. Brev kan hämtas ut i receptionen medans paket hämtas på Godisfabriken Supermarket i Abisko Östra.
Yes, you can send both letters or parcels here for a small fee, but you must contact the reception well in advance. Letters can be picked up at the reception whereas parcels are picked up at Godisfabriken Supermarket in Abisko Östra.
Note that there's also plenty of processed outdoor food for sale in Abisko (much cheaper than Norway), as it's a major hiking centre where many people start Kungsleden hikes. If you do your hike before mid-September, expect it to be very busy (~200 people per day).
Some unrequested advice:
- Lofoten is mostly not suitable for trekking but only for day hikes, unless you are happy with long sections of roadwalking. The trails mostly connect the road to mountain summits, you can't really walk along the chain anywhere west of Hinnøya. You will get most out of Lofoten if you stay in one place and rent a car to get to shorter or longer hikes. It's beautiful, but also busy, if you don't like crowds consider Senja as an alternative.
- If you have some experience and if you value solitude, consider some alternative routes in the area. I'm not sure how much time you have, but assuming you're bringing a tent, a lonely alternative is to start from Gratangseidet via Gussajávrrit, then south to Katterjåkk-Sjangeli-Unna Allakas and Nordkalottruta south from there. You can start further west than Gratangseidet as well, but I've found the trail from Tjeldsundbrua to Gratangseidet impossible to find and only locally spectacular. I've hiked a lot in the area, and I've found the terrain between Skjomen and Hellemobotn some of the most spectacular and lonely. From Gratangseidet all the way to Hellemobotn may be too far, though.
Between Baugevatnet and Sijdasjávrre, near Narvik, Norway, ~68.1°N, 1 October 2012. Probably less than 50 hikers per year pass here, we saw nobody for the 4 days from Hellemobotn to Skjomen.