Since hard carry is, in my opinion, the easiest role to play, I would try to safe trilane with a random if I were you. By your MMR, I presume that you probably know how to safe trilane, but I'm going to lay it out briefly anyways for others' benefit.
First, it's not literally a "tri-lane." That is to say if you have three people in the lane from your team at once and you aren't currently ganking the enemy hero(es) into next year, you are not doing it correctly. The tri-lane usually involves a carry and a babysitter as is normal for pub play, but there is a second support that consistently pulls your creep wave into the jungle so that they die to neutral creep and deny the enemy XP and gold. You can do this with a duo lane too, but it's riskier for your carry because they get left alone for at least half the time, and you're alone too which means that if mid ganks through jungle you are also paste. The support in the jungle gains XP by consistently pulling creep from the neutrals dying. He or she can also leave to gank mid or do some general roaming stuff, if you think that it is safe to duo lane for the moment.
Second, in terms of lane comp, you should be focused on "what heroes work well ganking or teamfighting together," not "what hero is the best at sustaining lane presence or helping my carry sustain his presence in lane." Undying and Visage are famously good trilane heroes in almost any comp because they both have skills that benefit greatly from more combatants being in a fight at once, and they're powerful early. Other possibilities include specific comps that synergize well together. A good one might be Ursa + Witch Doctor + Crystal Maiden. CM can set up easily with Frostbite, then WD moves into position and uses Maledict. Once Frostbite expires, WD stuns. Meanwhile the whole time Ursa is laying into them with Overpower and Fury Swipes. If they aren't dead outright then Maledict is guarenteed to kill them because between CM and Ursa you have a very large amount of early game burst damage, which translates into Maledict having huge ticks. That's just one I thought of off the top of my head, just think about the spells of all the heroes you've played and how they might work well together.
